With two layers of fluffy sponge and swooshes of fudgy frosting, this picture-perfect gluten-free chocolate cake recipe looks almost too good to be true. But this layer cake? She delivers. Her trick? Skip the store-bought all-purpose flour alternative and make your own gluten-free flour blend using nutty oat flour (which is naturally high in protein, providing structure), starchy sweet rice flour (to keep the crumb tender), and xanthan gum (to hold it all together).
While you could make oat flour by blitzing rolled oats in your food processor, we found commercial oat flours work best here (we like Bob’s Red Mill). Factory-milled flours tend to have a finer texture than their homemade counterparts, allowing them to absorb moisture more evenly, translating to a softer, fluffier cake.
To develop rich chocolate flavor and color, you’ll bloom unsweetened cocoa powder (Dutch-process, please) in hot water. Meanwhile, tangy buttermilk (or a baker-approved buttermilk substitute) brings out the chocolate’s bright, fruity notes. As for the pudding-like chocolate frosting, its texture lies somewhere in the Venn diagram of whipped cream, buttercream, and chocolate ganache. It’s also virtually indestructible; any problem you may encounter is fixable. Too soft? Chill it. Too firm? Let it sit at room temperature for a while longer. Looking split? Warm it gently until it smooths out.
For the best presentation, baking these in 8" round cake pans is imperative. Use 9" pans instead and the cake layers will be too thin and anemic-looking. And when you’re making a birthday cake (or any occasion cake) for someone who’s had their fair share of celiac-conscious catastrophes, you want to get everything just right. Good thing you stopped here.
Looking for a dense, brownie-like, flourless chocolate cake? We’ve got you. And head this way for more of our best gluten-free desserts and other baked goods →
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What you’ll need
Sweet Rice Flour
$2.99 At Weee!
Scale
$26 At Amazon
Electric Mixer
$40 At Amazon
8-Inch Cake Pan
$10 At Amazon
Whisk
$10 At Amazon
Small Offset Spatula
$9 At Amazon
Recipe information
Total Time
90 minutes (plus 1 hour for cooling)
Yield
8 servings
Ingredients
Cake
1½
1
½
2
1½
½
¼
1
⅓
2
⅔
1
Frosting and Assembly
1
¼
2
1
8
1
Preparation
Cake
Step 1
Place a rack in middle of oven; preheat oven to 350°. Lightly coat two 8"-diameter cake pans with nonstick vegetable oil spray; line each with a parchment paper round. Vigorously whisk 1½ cups (300 g) granulated sugar, 1 cup (160 g) oat flour, ½ cup (60 g) mochiko, 2 tsp. Diamond Crystal or 1¼ tsp. Morton kosher salt, 1½ tsp. baking powder, ½ tsp. baking soda, and ¼ tsp. xanthan gum in a medium bowl to combine.
Step 2
Whisk 1 cup (85 g) Dutch-process cocoa powder, ⅓ cup vegetable oil, and ¾ cup boiling water in a large bowl until cocoa is dissolved, about 30 seconds. Add 2 large eggs, ⅔ cup buttermilk, and 1 Tbsp. vanilla bean paste or vanilla extract and whisk to combine. Add dry ingredients to wet ingredients and whisk until just combined and batter is smooth. Divide cake batter between prepared pans (about 545 g per pan).
Step 3
Bake cakes until a tester inserted into the center comes out with a few moist crumbs attached and cakes spring back when gently pressed in the center, 22–28 minutes. Transfer pans to wire racks and let cakes cool in pans.
Frosting and Assembly
Step 4
Whisk 1 cup (110 g) powdered sugar, ¼ cup (21 g) Dutch-process cocoa powder, 2 tsp. vanilla bean paste or vanilla extract, 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt, and ¼ cup boiling-hot water in a medium bowl until smooth. Let cool, about 5 minutes.
Step 5
Meanwhile, heat 8 oz. semisweet or bittersweet chocolate (68–70% cacao) in a heatproof mixing bowl set over a saucepan of simmering water (bowl should not touch water), stirring, until chocolate is melted and smooth. Let cool slightly before using. (Alternatively, melt in a microwave-proof bowl in the microwave in 20-second bursts, stirring after each burst.)
Step 6
Add 1 cup (2 sticks) unsalted butter, room temperature, to powdered sugar mixture and, using an electric mixer (a stand mixer with paddle attachment or hand mixer with beaters) on medium-high speed, beat until smooth and creamy, about 2 minutes (it may look curdled at first, but keep beating). Scrape in melted chocolate; beat until combined, about 2 minutes. If frosting is soft (like pudding), chill, stirring often, just until cool to the touch and thickened to a scoopable texture, about 15 minutes.
Step 7
Run a small offset spatula around cakes to loosen and turn out onto racks. Remove parchment paper; discard. Place a cake, right side up, on a large plate or cake platter. Spread 1 cup frosting evenly over top of cake. Place remaining cake on top, arranging upside down. Spread remaining frosting over top and sides of cake, swirling decoratively if desired. Chill until frosting is sliceable but not too firm before serving, about 30 minutes.
Do Ahead: Frosting can be made 3 days ahead; cover and chill. Bring to room temperature, then whisk to lighten before using (reheat gently if it looks curdled). Cake can be assembled 1 day ahead; keep chilled. Bring to room temperature before serving.