A warm cookie in a mug — that's how this keto chocolate chip mug cake tastes, chewy center and all. My two-flour combo took weeks to get right and keeps it from going spongy. Ready in under two minutes at 3.6g net carbs.
I've been making this chocolate chip mug cake since I started testing single-serving keto desserts back in 2019, and it's the one I come back to more than any other. Not because it's the fanciest recipe on the site, but because it genuinely tastes like a warm chocolate chip cookie. That's not marketing. Reader Alicia P. made it for her 8-year-old, and her daughter said it tastes "exactly like a cookie." I know, because my boys say the same thing.
The secret is the two-flour combo. Most recipes like this use either almond flour or coconut flour. I use both. The almond flour gives you structure and that nutty richness, while a small amount of coconut flour absorbs excess moisture and creates the dense, chewy texture that separates this from spongy microwave bread. I tested it with almond flour alone and it was too loose. Coconut flour alone was too dry. Together, they just work.
The whole thing takes about a minute of prep and 60-85 seconds in the microwave. I've tested this in three different microwaves and the sweet spot is around 70 seconds in a standard 1000W model. You want the top to look set but still slightly soft in the very center. It firms up as it cools. If you microwave it until it looks fully done, you'll end up with rubber. Pull it early and trust the carryover.
I pour the batter into one large mug when I want a thick, gooey center, or split it between two smaller mugs when my kids both want one. Both ways work. Just make sure your mug is at least twice the volume of the batter because it rises fast and will overflow a small cup.
If you want more single-serving keto desserts, I have a whole collection. My chocolate version is rich and fudgy for when you want pure cocoa. The birthday version is what I make when someone in the house is celebrating and doesn't want a full cake. The pecan pie version tastes like Thanksgiving in a cup. And if you want something totally different, the red velvet one has a similar texture with a completely different flavor.
This is a sugar-free dessert you can make without planning ahead, without preheating anything, and without dirtying more than one bowl and a mug. I keep all the dry ingredients in my pantry and can have it ready before the kettle boils. For a low carb treat that actually satisfies a real craving, this is what I reach for every time.
One single serve cake, baked in the microwave in 60 to 85 seconds.
I like baking this in a ramekin instead of a mug because it cooks more evenly and looks prettier.
The oven version, baked in a ramekin, comes out a little firmer than the microwave one.
Easy Keto Chocolate Chip Mug Cake in the Microwave Ingredients
Step by Step Instructions
1
Combine the ingredients
Combine all ingredients in a small bowl and mix until combined.
2
Pour the batter
Pour mug cake batter in a large greased mug or into two greased with cooking spray.
3
Microwave it
Microwave for 60 to 85 seconds or until the cake has risen and is set in the middle (not wobbly). Remove from microwave to let cool before eating.
Nutrition
Per serving: 1 mug cake
Calories
422
Fat
38.7g
Protein
9.9g
Total carbs
10.3g
Net carbs
3.6g
Nutrition is an estimate calculated from the ingredients listed. Brands vary, so check labels if you track closely.
Frequently Asked Questions
Can I bake this in the oven instead of the microwave?
I've done it at 350°F for about 12 minutes in a ramekin. The texture comes out slightly firmer, more like a low carb cookie bar than the soft, gooey center you get from the microwave. Both are good, just different. I still prefer the microwave version because the whole point is speed. If you're already heating up the oven, my keto chocolate cake is worth the extra time.
Why did my mug cake come out rubbery?
Two things cause this: overmixing and overcooking. I just stir until the dry ingredients are incorporated and stop. No need to beat it smooth. And pull it from the microwave when the top looks set and the center no longer wobbles. It firms up as it cools. The first time I made this, I left it in for a full 90 seconds and it bounced like a rubber ball. Now I start checking at 60 seconds.
What size mug should I use?
I use a 12-ounce mug and it works perfectly. The batter fills it about halfway, which gives it room to rise without overflowing. I've also split it between two smaller mugs (about 8 ounces each) when my kids both want one. Anything under 10 ounces for a single batch and you'll be cleaning your microwave.
Can I make this dairy-free?
I've swapped the butter for coconut oil and it works. The texture stays the same, maybe slightly denser. I haven't tried ghee but I'd expect similar results. The flavor shifts a little (you lose that buttery richness), but with the chips in there you barely notice.
Can I use a different flour instead of almond flour?
Coconut flour works, but you need way less. I use 1 tablespoon of coconut flour instead of the 2 tablespoons of almond flour, and add about a tablespoon of extra liquid (milk or water). Coconut flour is much more absorbent, so if you use the same amount you'll get something dry and crumbly. I tested both side by side and the almond flour version has a better cookie-like chew. If you want to explore almond flour baking further, my almond flour cookies use a similar ratio.
What sweetener works best?
I use monkfruit sweetener because I like the taste and it measures 1:1 with sugar. Erythritol works too but can leave a slight cooling sensation. I've tried stevia drops and they work in a pinch, but sweetness levels vary a lot between brands so start with less and adjust. For a sugar-free dessert this small, the sweetener choice really comes through, so use one you actually like the taste of.
How do I store leftovers?
I keep leftovers in an airtight container in the fridge for up to 2 days. A quick 10-15 seconds in the microwave brings it back. Honestly though, I usually eat the whole thing in one sitting. If I know I'll want another one tomorrow, I just make a fresh batch since it takes two minutes.
Can I add toppings?
I top mine with a spoonful of whipped cream and a few extra chips while it's still warm so they get melty. Chopped pecans or walnuts are good too. If you want a totally different single-serving dessert, my pumpkin version is what I reach for once fall hits.
Chewy in the middle, which honestly surprised me, I figured microwave cake meant rubbery. This is my fourth or fifth one now and I’ve settled on pulling it just over a minute. I use a wider mug than I started with and the top sets more evenly that way! Best two minutes of my night, no question.
Halfway through stirring, the batter smelled just like the cookie dough my mom used to let me lick off the spoon. I honestly forgot about that until last night. It came out chewy in the middle, not spongy like other microwave cakes, and I sat there with the mug feeling like a kid again. Thank you for putting this one together.
Mix the dry ingredients before adding the egg, blends cleaner. Expected eggy microwave batter and this passes the test it usually fails. Four stars because 422 calories is still a commitment.
I mix everything at once and get a flour pocket at the bottom every time. Dry-first is cleaner, using that next batch. The 422 is mostly fat, which is supposed to keep you full until dinner.
Mine is 1000W, so yes, 1200W runs faster. I’d pull 15-20 seconds early and watch the center, not the timer. The second the edges look set but the middle still wobbles, take it out.
Out of coconut flour right now. Would doubling the almond flour to 4 tbsp work, or does coconut flour do something specific for texture that almond can’t?
Coconut flour absorbs way more liquid, so 4 tbsp almond straight will make it dry and dense. Try 3 to 3.5 tbsp total. Center won’t be as chewy but it’ll set.
Brought ingredients to a friend’s place and made these after dinner. Two-minute turnaround turned into a whole event, everyone hovering around the microwave. The coconut flour smell did more convincing than anything I could’ve said about keto.
That smell sells it before the first bite. I brought ingredients to my sister’s last month, same exact situation, someone asked what was in it while it was still in the microwave. Coconut flour does that. Two minutes is short enough that nobody wanders off, and then it comes out warm with the chips still soft.
My kids saw this on my phone and now both want one tonight. Can I just triple the batter and split it into three mugs, or does that mess with the almond flour to coconut flour ratio? And does microwave time stay around 60-85 seconds per mug if I’m doing them back to back?
Natalie, tripling is fine since each mug still gets a full single batch, so the ratio stays put. Time is the same per mug too. I’d start checking at 60 seconds on the later ones since the microwave stays warm.
Tried at least five other keto mug cakes before this one and they all came out like spongy rubber. The two-flour combo actually nails that chewy center, like a real cookie instead of a microwave accident. Done looking.
Not usually a mug cake person (they’re always spongy and sad), but the two-flour combo here actually delivers that chewy center. Do you think swapping the butter for cream cheese would work if you want to bump the fat macros a bit?
Cream cheese won’t bump the fat macros. Butter is higher fat per tablespoon, so you’d actually drop a little on the swap. It’ll work, texture just shifts to denser and slightly tangy, more cream cheese brownie than chewy cookie center.
Stirred in an extra tablespoon of Lily’s chips beyond what the recipe calls for and microwaved the full 85 seconds (I have a lower-watt microwave) and the center came out perfectly gooey. The two-flour combo really does make it taste like an actual cookie, not that spongy texture I was bracing for. Making this every Sunday now.
Extra Lily’s in the center never hurts. And yeah, 85 seconds sounds right for lower-watt, the center should still have a little jiggle when you pull it.
I am not a baker. Like, not even close. So when I saw this only needed a handful of ingredients and a microwave, I figured it was worth trying. The two-flour combo threw me a little (I didn’t even know coconut flour was a thing before this), but I just followed along and microwaved it for about 75 seconds. When I pulled it out the center still looked soft and I was convinced I’d messed it up, but after about 30 seconds it set up and the texture was completely different from what I expected. Not spongy at all, more like the middle of a warm cookie fresh out of the oven. The chocolate chips were still melty throughout and I’m pretty sure I made a noise. Three weeks into keto and I had basically given up on ever having something that felt like actual dessert.
That 30 seconds where you think you’ve wrecked it is the worst. The coconut flour is still working after the microwave stops, it needs that rest to set. Three weeks in and you got it first try.
I’ve never made a mug cake before and was bracing for something rubbery and sad. The chewy center is freaking real (the two-flour thing actually does something), but mine was still a touch soft at 80 seconds. Is that normal or do I push it to 85?
80 seconds is fine if the top looks set. The center’s supposed to come out a little soft, it firms up as you eat it. I’ve pushed past 85 and it goes rubbery fast.
Premixed the dry ingredients in five separate ramekins so each night I just add egg, butter, and vanilla. 90 seconds. Real dessert, not a consolation prize. The two-flour combo is what keeps me from getting bored after a week straight. Been using Lily’s chips and the macros land exactly where I need them every time.
The ramekin system is such a good call. And Lily’s are the ones I keep coming back to too. Every other brand I’ve tried throws the macros just enough to be annoying.
My son grabbed the mug before it even cooled down and burned his fingers trying to scoop it out. That reaction told me more than any taste test could. The two-flour combo is what gets it right, that chewy center instead of the rubbery texture I’d accepted from every other mug cake I’d made. Four times this week. He’s stopped asking for regular cake after dinner.
Burned fingers are basically the best review I’ve ever gotten for this. Four times in a week and he’s already moved on from regular cake. That two-flour combo took me forever to get right, so I’m glad it’s doing what it’s supposed to.
Been keto almost a year and gave up on dessert a while back, figured the substitutes were never worth it. Made this on a quiet Tuesday night when the craving hit hard, and I genuinely teared up a little. That chewy center from the two flours is the thing I thought I’d just never get back.
Stirred a tablespoon of peanut butter in with the melted butter and the center came out so much richer. The two-flour combo is already great for texture, but the peanut butter version is a different thing entirely (in a good way). One note: mine needed the full 85 seconds to set instead of 60, so give it the extra time if you try it.
My 8-year-old has been asking for chocolate chip cookies literally every day this week and I needed something fast that wouldn’t wreck my macros. Made this in like 3 minutes and she ate the whole thing (I had to make a second one for myself). She said it tastes exactly like a cookie and honestly she’s not wrong, the texture is spot-on. We’re doing this every time she gets that look on her face now.
8 year olds don’t lie about texture. If she said cookie you nailed it. I make these when my boys want something sweet but I need it done before they change their minds.
