Crazy Cake Recipe

Preheat oven to 350°F (175°C). Grease and flour a 9x13-inch baking pan or line it with parchment. Alternatively, spray with nonstick spray.

Combine dry ingredients

In a large mixing bowl, whisk together 2 cups all-purpose flour, 1.5 cups granulated sugar, 1.75 cups unsweetened cocoa powder, 1.5 tsp baking soda, and 0.5 tsp salt until evenly distributed and no lumps remain.

Add wet ingredients

Make three small wells in the dry mixture. Pour 0.5 cup vegetable oil into one well, 1 tablespoon white vinegar into the second well, and 1 teaspoon vanilla extract into the third well. Pour 1 cup cold water evenly over the whole mixture.

Mix batter

Using a sturdy spatula or whisk, mix until just combined and smooth, scraping the bottom to incorporate any pockets of dry flour. Batter will be fairly loose and glossy. Do not overmix.

Pour the batter into the prepared 9x13 pan and smooth the top with an offset spatula or back of a spoon. Bake in the preheated oven for 25–30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs but no raw batter.

Remove from oven and allow cake to cool in the pan on a wire rack for 15 minutes. If frosting right away, leave warm or slightly warm; to frost later, cool completely before icing.

Beat butter and cocoa

In a medium bowl, beat 1/4 cup softened unsalted butter and 1/4 cup unsweetened cocoa powder together until smooth and slightly fluffy, about 1 minute.

Add powdered sugar and milk

Gradually add 1.5 cups powdered sugar, alternating with 2 tablespoons milk (or cream), beating to a spreadable consistency. Add more milk, 1 teaspoon at a time, if too stiff, or a little more powdered sugar if too thin.

Finish frosting

Stir in 1/2 teaspoon vanilla extract and 1/8 teaspoon salt, then beat 10–20 seconds more until glossy. Taste and adjust salt or vanilla as desired.

Frost cake

When the cake is warm (for a slightly melted frosting effect) or completely cool (for a stable finish), spread the frosting evenly over the top with an offset spatula. Slice and serve. Store leftovers covered at room temperature for up to 2 days or refrigerated for up to 5 days.