· 1/4 cup/25 grams unsweetened cocoa powder (Dutch-processed or natural)· 1 to 2 ounces chopped bittersweet chocolate (optional)· 3/4 cup/180 milliliters boiling water, or use hot coffee, Earl Grey tea or mint tea· 2/3 cup/160 milliliters mayonnaise· 1/4 teaspoon kosher salt· 1 1/2 teaspoons baking soda· 3/4 cup/150 grams granulated sugar· 1 teaspoon vanilla extract, or a dash of bourbon or whiskey (optional)· 1 1/2 cups/190 grams all-purpose or cake flour· Flavorless oil or another grease, for the pan· Confectioners’ sugar, for finishing
Step 1To a large mixing bowl, add cocoa powder and chopped bittersweet chocolate (if using). Pour in boiling liquid, and let it sit for a few minutes, then whisk until smooth. The chocolate will have melted, if you used it, and the cocoa dissolved.Step 2Whisk in mayonnaise, salt, baking soda, 3/4 cup granulated sugar until smooth. Then whisk in a teaspoon of vanilla extract, if you have it (or a dash of Bourbon or brandy or just leave it out entirely). Finally, whisk in 1 1/2 cups flour (either all-purpose or cake flour), mixing vigorously to eliminate any lumps.Step 3Grease an 8- or 9-inch pan (square, round, star-shaped, anything is good). Pour the batter into the pan, and bake at 350 degrees for 22 to 40 minutes, until the top springs back when the center is lightly pressed. The deeper the pan, the longer it will take to bake through.Step 4Let cool, and sprinkle with confectioners’ sugar to finish.