Keto Maple Mustard Green Beans
Published November 16, 2019 • Updated March 3, 2026
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I roast these keto maple mustard green beans at 450°F with a two-mustard glaze that caramelizes into something sweet, tangy, and slightly spicy. The lemon squeeze at the end pulls everything together.
I started making these because I wanted a side dish that actually competed with the main course. Not just “green beans on the plate” but something people reached for seconds of. The trick is roasting at 450°F, which is higher than most recipes call for. That extra heat drives real caramelization on the edges instead of just softening the beans through.
The glaze uses two mustards on purpose. Dijon emulsifies and clings to every bean, while stone ground adds these visible texture pops that you can actually feel when you bite in. They’re doing different jobs. I tested it with just dijon once and it was fine, but flat. The stone ground is what makes people ask what’s in the sauce.
Here’s the technique that took me a few rounds to figure out: the sauce goes on halfway through, not before. I toss the beans in just olive oil and salt first so they start crisping at that high heat. If you put the maple syrup mixture on from the start, the sugars scorch before the beans even cook through. Ten minutes plain, then brush on the glaze, then back in for another 10-12 minutes. The glaze caramelizes without burning.
The lemon juice goes on after the oven, not before. I tried it both ways. When you roast the lemon juice, it cooks off and you lose that bright acid that cuts through the maple sweetness. A squeeze of fresh lemon right when they come out rounds the whole thing out. Sweet from the maple syrup, tangy from the mustard, a little heat from the cayenne, then that lemon brightness at the finish.
If you like green beans as a side, I also make keto green beans and bacon for nights when I want something smokier. For holiday tables, these sit well next to keto cranberry pecan Brussels sprouts or loaded mashed cauliflower. I’ve also served them alongside keto sauteed mushrooms and oven roasted asparagus when I’m doing a full low carb spread.
This is one of those sides I come back to because the flavor payoff is big for how little work it actually is. Toss, roast, brush, roast, squeeze lemon, done. If you want a bread on the side, my keto cornbread pairs really well with the maple mustard flavor. And if you’re looking for another low carb vegetable dish, cheesy basil zucchini is another one I keep in rotation.
Ingredients
1 tablespoon sugar free maple syrup -
1 tablespoon dijon mustard
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1 tablespoon stone ground mustard
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pinch of cayenne pepper
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1 pound of green beans, stems snapped off
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1 tablespoon olive oil
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1/2 teaspoon salt
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juice from 1/2 lemon
Step by Step Instructions
Step by Step Instructions
Preheat oven
Preheat oven to 450 degrees.
Make the maple mustard sauce
In a small bowl, combine ChocZero maple syrup, mustards and cayenne pepper.
Roast the beans
Spread out green beans on a baking sheet lined with aluminum foil. Drizzle olive oil and salt. Toss to coat the beans. Spread out again in an even layer to allow for uniform cooking. Roast for 10 minutes at 450 degrees.
Brush on maple mustard
Remove tray from oven and brush the maple mustard mixture all over the green beans. Return to the oven and roast for 10 to 12 minutes longer.
Finish with lemon
Once roasted, remove from the oven. Season with more salt if needed. Squeeze 1/2 lemon over the green beans.
Nutrition disclaimer
The nutrition information provided is an estimate and is for informational purposes only. I am a Doctor of Pharmacy (Pharm.D.); however, this content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always consult your physician or other qualified health provider before making any lifestyle changes or beginning a new nutrition program.
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Get My Macros + Recipes →Frequently Asked Questions
Can I use only dijon mustard if I don't have stone ground?
I've made this with just dijon and it works. The sauce coats the beans well and the flavor is still good. But I noticed it loses that textured bite the stone ground seeds give you. If I only have dijon, I'll sometimes stir in a tiny bit of whole grain mustard or even crushed mustard seeds to get some of that crunch back. Dijon alone is solid though, just smoother.
What brand of sugar free maple syrup works best?
I use ChocZero maple syrup because it caramelizes well at high heat without getting bitter. Some sugar free syrups have a cooling aftertaste from certain sweeteners, and that's not what you want on roasted green beans. I've tried a few brands and ChocZero has been the most consistent for cooking. Lakanto is my second choice if I can't find ChocZero.
Can I make these in the air fryer?
I've done it and they turn out well, just different. I set my air fryer to 400°F, toss the beans in olive oil and salt, and cook for about 8 minutes. Then I brush on the maple mustard glaze and go another 4-5 minutes. The edges get even crispier than the oven version, but you have to work in smaller batches so they don't steam. I can fit about half a pound per batch in my keto side dish rotation this way.
Can I use frozen green beans instead of fresh?
I tried frozen once and the results weren't great. Frozen beans release a lot of water when they hit 450°F, so instead of roasting they steam on the pan. The glaze slides right off. If frozen is all you have, I'd thaw them completely first, then pat them really dry with paper towels before oiling. But fresh beans give you that snap and char that makes this recipe work.
Do these reheat well or do they get soggy?
They reheat fine if you use the oven. I spread leftovers back on a sheet pan at 400°F for about 5 minutes and they crisp up again. The microwave makes them a little soft, and you lose that caramelized edge. I've stored them in the fridge for up to 3 days with no issues. The glaze actually intensifies overnight, so day-two beans have a deeper flavor.
How do I get the green beans crispy and not limp?
Three things I learned the hard way. First, single layer on the pan. If the beans overlap, they steam instead of roast. Second, make sure they're dry before you oil them. Any extra moisture fights the crisping. Third, the sauce goes on at the halfway mark, not before. I put the glaze on too early my first time and the sugars burned while the beans stayed soft. Oil and salt first, let them start crisping, then add the glaze.
Can I make these ahead for Thanksgiving or Christmas?
I do this every holiday season. I prep the maple mustard sauce up to 3 days ahead and keep it in the fridge. I also trim and wash the beans the night before. When it's go time, I just toss, roast, and glaze. The whole thing takes about 25 minutes from cold oven to table. I wouldn't fully cook them ahead of time though, because reheated beans never have the same snap as fresh-from-the-oven.
Can I make this recipe spicy?
I bump up the cayenne when my husband and I eat these without the kids. A full 1/4 teaspoon gives noticeable heat without overpowering the maple sweetness. I've also tossed in red pepper flakes right after the oven, which gives you visible flakes and a different kind of heat. The cayenne blends into the glaze; the flakes hit you in bursts. I like both depending on my mood.
I love green beans, especially around the holidays. No Thanksgiving dinner is complete with them. This is an easy holiday side dish that you can make for your holiday dinner or bring to a potluck. They are also perfect paired with a simple weeknight dinner, like 
Although traditional maple syrup is not keto friendly, there are sugar free versions available that are. 
Green beans have a higher carb count than other green vegetables. If you eat them in moderation, they are still fine on a low carb diet. One cup of cooked green beans has 10 grams of total carbs and 6 net carbs.
We don’t eat them too often but around the holidays, it’s a must. I can’t have turkey without a side of green beans. Plus there are other nutritional benefits to green beans. They have lots of vitamin C and silicon (good for bone, skin and hair).
To trim green beans you can line up the stem side of the green bean and slice off the stems. You can also snap off the stem side one by one. The other end, you don’t need to remove. This side is tender and perfectly fine to eat.
Most mustard works great here; although, it’s worth reading the nutrition label to make sure there are no sugars added. I like to use two different mustards in this recipe. The stone ground mustard provides flavor and I like the appearance of the ground mustard on the green beans. If you don’t have access to stone ground mustard, you can double the amount of Dijon mustard in this green bean recipe.
I only have dijon on hand. Can I just use two tablespoons of that, or does stone ground actually change the texture of the glaze?
Yeah, two tablespoons of dijon works. I've made it that way and the glaze coats the beans just fine. What you lose is that coarser, seedy texture from the stone ground. Flavor's still good, just smoother.
My son hasn't willingly eaten a vegetable since 2024. He cleaned his plate and asked for seconds. Maple mustard at 450 just does something to them.
My son grabbed green beans off the tray before I could plate them. Nine years of dinners and that has never happened. Has to be the caramelized edges from that maple mustard hitting the hot pan.
Used a mix of broccolini and green beans because that's what I had, and the broccolini charred a little faster at 450 but in a good way (got those crispy floret tips with the maple mustard caramelized on). Might like it better than all green beans, though I'd pull the broccolini out a minute or two early next time.
Brought these to Easter dinner and someone scraped the last of the glaze off the pan after the beans were gone.
Ha. The glaze at 450 gets sticky and almost candied and people never see it coming.
First time roasting green beans and I went straight to 450 with the two-mustard glaze. The caramelization hit different than I expected, that sweet-tangy edge with the cayenne underneath. Genuinely did not know a vegetable side could do that. One question though: does the lemon timing matter much? I squeezed it on right at the end like you said and it tasted right, but I want to understand the why before I start experimenting.
The acid evaporates at that heat. Put it on before and by the time the beans come out, it's just gone. End of cooking is when it actually cuts through the glaze instead of cooking off.
Most roasted green bean recipes I've tried are either too sweet or too flat. The two-mustard combination at 450 gets you real caramelization without losing the tang, and the lemon at the end keeps it from going heavy. This is the one I'm using from here on.
Took me a while to get the lemon timing right. Add it before the oven and it just steams off. Has to be the last thing.
Fourth time making these. I finally started brushing the glaze on halfway through instead of all at once, and the caramelization is so much better that way. Stickier, edges get almost jammy. The stone ground mustard really comes through once it hits that heat. I'd been skipping the lemon squeeze but tried it this time and yeah, that's not getting skipped again.
The jammy edge is the goal. Halfway in gives the glaze time to set before it burns off. And the lemon, once you've had it there's no going back.
I've made probably four different roasted green bean recipes trying to find one that actually tastes like something, and this is the one. The two-mustard glaze caramelizes into this sweet-tangy thing I wasn't expecting, and the lemon at the end makes it pop.
The cayenne is quiet but it rounds out the sweetness. I bump it to 1/4 teaspoon when I'm not serving it to my kids.
Made these for Sunday dinner and the glaze is seriously something, the stone ground mustard adds this subtle grainy texture that makes it feel more legit than a smooth sauce would. My one thing: if your green beans are on the thicker side, roast them a few extra minutes before you brush the glaze on. I didn't, and the coating caramelized fast while the beans were still a little firm inside. Made them again with the extra roast time and completely different result. The lemon at the end is non-negotiable, by the way.
Yes on the extra roast time. Thicker beans hold more moisture and the glaze sets before the inside catches up. Figured that out the same way. The lemon pulls everything together, can't skip it.
Green beans that survive meal prep without turning to mush are rare, and these do it. The mustard glaze deepens after two days and the dijon gets more pronounced. Quadrupling the batch next Sunday.
Yeah the mustard keeps working after the oven. The cayenne builds too. Two sheet pans for four pounds though, single layer or they'll steam instead of roast.
Making these tonight and only have dijon. Will that work on its own, or is the stone ground doing something specific in the sauce?
Yeah dijon works. You'll lose the grainy, seeded texture the stone ground gives the glaze, but the flavor holds up fine.