The gluten-free flours used in this recipe, available at Bob's Red Mill and natural-foods stores, yield delicate results. The cake is best eaten right after it's decorated. To ensure that the layers rise properly (and don't sink), avoid opening the oven door as they bake. We've tinted the finished frosting pink by adding red gel-paste food coloring drop by drop. Feel free to leave it white, or tint it with any favorite color.
Martha Stewart Living, April 2009
Yield Serves 8
For the Cake Layers
Vegetable oil cooking spray
11/2 cups sugar
3/4 cup brown-rice flour (see the Guide)
1/2 cup almond flour (see the Guide)
3/4 cup unsweetened Dutch-process cocoa powder
1/4 cup quinoa flour (see the Guide)
2 teaspoons baking soda
1 teaspoon baking powder
3/4 teaspoon coarse salt
2 large eggs
3/4 cup warm water
3/4 cup low-fat (1 percent) buttermilk
1 ounce (2 tablespoons) unsalted butter
1 teaspoon pure vanilla extract
For the Seven-Minute Frosting
1 1/4 cups sugar
1/4 cup water
1 tablespoon plus 1 teaspoon corn syrup
5 large egg whites
3/4 teaspoon pure vanilla extract
Pinch of salt
Make the cake layers: Preheat oven to 350 degrees. Lightly coat two 8-inch cake pans with cooking spray. Line bottoms with parchment; spray parchment.
Whisk together dry ingredients in a large bowl. Add remaining ingredients, and mix until smooth, about 3 minutes. Divide batter between pans.
Bake cakes until they pull away from sides of pans, about 1 hour. Let cool in pans on wire racks. Cakes will keep, covered, for up to 1 day.
Make the frosting: Place sugar, water, corn syrup, and whites in a heatproof mixer bowl over a pot of simmering water. Cook, whisking occasionally, until sugar dissolves and mixture registers 160 degrees on a candy thermometer.
Attach bowl to mixer. Whisk hot sugar mixture on high speed until stiff, glossy peaks form, about 7 minutes. Whisk in vanilla and salt.
Assemble the cake: Place a cake layer on a plate. Spread 2 cups frosting on top. Place remaining cake layer on top of frosting. Frost top and sides with remaining frosting. Cake is best eaten within 1 hour of frosting.