I made this chocolate-matcha butter mochi cake for Passover (because rice is kosher for Passover now, don’t @ me).
I really liked the cake, though I felt like it was a bit too oily. It is based on traditional Hawaiian butter mochi cake – I’d never heard of it, which I take as a sign from the Universe that I need to spend more time in Hawaii! Based on this recipe, one could reduce the amount of butter to essentially use a ratio of about ½ cup of butter for the box of mochiko flour; in this recipe, I used half the box, so I’d try ¼ cup of butter in this cake next time. Mochiko is also called sweet rice flour or glutinous rice flour (though it contains no gluten, only starches); it is NOT the same as white rice flour or brown rice flour, and you CANNOT substitute.
Mochiko is really what gives this cake its special chewy texture, the same as in mochi. Also, while it is true that using fresh, ceremonial-grade matcha tea will give you a much brighter, vibrant green, I had an old bag of matcha in the pantry and wasn’t about to source a second one just for this, so a dull green will have to do. That being said, it was delicious, and I just loved the chewy texture!
6 Tbsp. lactose-free butter, melted and slightly cooled (I’d use 4 Tbsp. next time)
1 ½ cups (227 g) mochiko (sweet rice flour)
1 tsp. baking powder (omit for Passover, obviously)
½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt
2 Tbsp. matcha, sifted, plus more for serving
2 large eggs
14 oz. lactose-free sweetened condensed milk (I used sweetened condensed coconut milk)
1 tsp. vanilla extract
1 1/3 cups lactose-free cream or substitute, divided
4 oz. bittersweet chocolate, chopped
Place a rack in middle of oven; preheat to 350 °F. Generously grease an 8"- or 9"-diameter cake pan (I used an 8” springform pan).
Whisk mochiko, baking powder, salt, and 2 Tbsp. matcha in a large bowl just to combine. Vigorously whisk eggs and melted butter in a medium bowl until pale and emulsified, about 30 seconds. Add sweetened condensed milk, vanilla, and 1 cup cream and whisk until mixture is smooth. Scrape into dry ingredients and whisk vigorously until smooth and very thick. Scrape batter into prepared pan and smooth surface.
Bake cake until it starts to pull away from sides of pan, top and edges are golden, and a tester inserted into the center comes out clean, 35–45 minutes (a cake in the smaller pan will take longer to bake than one in the larger pan – my cake took 45 minutes). Transfer pan to a wire rack and let cake cool 5 minutes. Turn cake out onto rack; let cool completely.
Place chocolate in a small heatproof bowl. Bring remaining ⅓ cup cream to a boil in a small saucepan. Immediately pour over chocolate; let sit 15 seconds. Stir until ganache is smooth.
Evenly pour ganache over top of cake. Using a small offset spatula or spoon, spread ganache to edges of cake (drips down the sides are encouraged!). Let sit until ganache is set, about 2 hours. (If you are in a hurry, you can chill the cake until glaze is set, about 30 minutes.)
Just before serving, dust top of cake with more matcha with a fine-mesh sieve.
(The cake and glaze can be made, separately, 2 days ahead. Store cake tightly wrapped in plastic at room temperature. Let glaze cool, then chill in an airtight container. Gently reheat glaze in the microwave or a double boiler over a pan of simmering water until just melted before using.)