3 cups (360g) King Arthur Unbleached All-Purpose Flour or King Arthur Gluten-Free Measure for Measure Flour
1 ½ cup (297g) granulated sugar
¾ cup (63g) King Arthur Triple Cocoa Blend
2 ½ teaspoon baking soda
2 teaspoons espresso powder, optional*
½ teaspoon table salt
1 batch Super-Simple Chocolate Frosting, prepared
Preparation
Preheat the oven to 350°F with a rack in the center. Lightly grease a 9" x 13" pan.
In a large bowl, whisk together the mayonnaise, water, and vanilla to dissolve the mayonnaise and form a thin, homogeneous mixture.
Sift in the flour, sugar, cocoa, baking soda, espresso powder, and salt. Whisk to combine. Pour the thick batter into the prepared pan and spread it into an even layer.
Bake the cake for 30 to 35 minutes, until a toothpick or thin knife inserted into the center comes out clean, or with a few moist crumbs clinging to it.
Remove the cake from the oven and let it cool in the pan on a wire rack.
Once completely cool, finish the chocolate mayonnaise cake with your frosting of choice (see “tips,” below, for ideas).
Store leftover cake, well covered, at room temperature for several days; freeze for longer storage.