Raindrop Cake

How to make this translucent dessert

My version skips the traditional soybean powder and sugar syrup. Here’s how I make it.

1. Boil water, agar agar powder, and sugar-free sweetener together.
2. Stir in vanilla extract and the remaining water.
3. Divide the mixture into 2-3 bowls if you want colored or cream-based versions. Keep one bowl clear. Add 1/4 cup heavy cream or coconut cream and food coloring to the others.
4. Pour into silicone molds. For edible flowers, fill molds halfway, press in the flower, then top off with the remaining mixture. This suspends them in the center instead of letting them sink to the bottom.
5. Refrigerate for 30 minutes or until set.

Getting a crystal clear result

I’ll be honest: my versions aren’t always perfectly crystal clear. This recipe is meant to be a quick, fun adaptation, not a technique showcase. But if clarity matters to you, here’s what I’ve learned after testing this more times than I can count.

• Use quality water. The original Japanese version uses water from the Southern Alps of Japan. Tap water sometimes has sediment that makes the gel slightly hazy. Filtered or mineral water helps.
• Dissolve agar powder fully. I add it slowly to the pot while stirring constantly. It starts cloudy and clears up as it heats. I look for no visible granules and a mostly clear liquid before adding the rest of the water. If you get clumps, strain through a fine mesh sieve.
• Hit a real rolling boil. This is the step that catches most people. Agar has to reach a full boil to activate, not just a simmer. If yours didn’t set, this is almost always why.
• Use less agar if possible. You need just enough to hold the shape without the gel getting too stiff. I’ve experimented with slightly reducing the amount and it gives a more delicate, wobbly result.

What is agar agar powder (and why I use it)

Agar agar (or agar powder) is a plant-based gelling agent used in Asian cuisines and in desserts like jellies, puddings, and custards. If you’ve made my keto gummy worms, you’ve worked with a similar concept, though those use gelatin instead.

I prefer agar for this recipe because it’s odorless, tasteless, and gives a cleaner, more translucent result than gelatin at the same concentration. It’s also naturally vegan. The catch is you have to boil it fully (a simmer won’t cut it), and it sets at room temperature rather than requiring refrigeration. That’s actually why these cakes can soften if you leave them out too long.

Traditional toppings (and what I use instead)

Traditional Mizu Shingen Mochi comes with two specific accompaniments:

• Kuromitsu (black sugar syrup): A thick, dark brown syrup made from caramelizing black sugar and water. Obviously not sugar-free. For a swap, I make a simple syrup with allulose and about half a teaspoon of blackstrap molasses for color. Not identical, but it gets you in the neighborhood.
• Kinako (soybean powder): A flour made from roasted soybeans. Kinako is actually naturally low in carbs, so you can dust this on without worry. It has a nutty flavor similar to peanut butter.

What I actually serve with mine:

• Whipped cream (my go-to)
• Sugar-free chocolate syrup
• A few berries on the side
• Crushed keto candy for crunch

Storage and serving tips

I store these in the refrigerator for up to 5 days. I keep them in the molds until I’m ready to serve, which protects the shape and prevents them from picking up fridge odors (a tip from reader Keisha that I now follow every time).

Plan to serve within 20-30 minutes of unmolding. At room temperature, the agar gel softens and the dome starts to flatten. This is not a dessert you can plate an hour before guests arrive. I set them out right as we sit down. Reader Drew found that using coconut cream instead of heavy cream gives a noticeably firmer set, which helps if you need a little more counter time. For a dairy-free dessert that holds up longer at the table, try my dairy-free ice cream.

These do not freeze well. The gel structure breaks down and they won’t hold their shape after thawing.