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Ingredients
Cake
- nonstick vegetable oil spray for the pan
2 cups granulated sugar 400 g
1 ¾ cups all-purpose flour 219 g- 1 teaspoon baking soda
- ¾ cup Dutch-process cocoa powder 64 g
¾ cup vegetable oil- 1 cup hot water
- 2 large eggs
- ¾ cup well-shaken buttermilk
- 2 teaspoons Diamond Crystal kosher salt or 1 1/4 teaspoons Morton for the base recipe
2 teaspoons vanilla extract
Frosting
¼ cup unsalted butter for browning- ⅓ cup nonfat dry milk powder 32 g
⅔ cup heavy cream- 1 cup unsalted butter at room temperature
- 2 ½ teaspoons Diamond Crystal kosher salt or 1 1/2 teaspoons Morton for the base recipe
- 1 teaspoon vanilla extract
- 1 lb powdered sugar 453 g, sifted
To finish
- flaky sea salt optional
- sprinkles optional
Equipment
Equipment images are illustrative. Exact products may vary.
Instructions
- Heat the oven to 375°F with a middle rack. Line the bottom of a 13-by-9-inch metal pan with parchment and lightly coat the parchment and pan sides with spray. Whisk the granulated sugar, flour and baking soda in a bowl.
- In a larger bowl, whisk the cocoa, oil and hot water for about 30 seconds, until the cocoa is dispersed. Whisk in the eggs, buttermilk, cake salt and vanilla. Add the dry mixture and whisk just until smooth. Scrape into the pan.
- Bake for 25–30 minutes, until springy and a tester comes out with a few moist crumbs but no wet batter. Cool completely, about 1 hour, before frosting. The cake can stay in its pan.
- For the frosting, warm the separate 1/4 cup butter in a skillet over medium-low heat until foamy. Add the milk powder and stir continuously for about 5 minutes, until a dark nut-brown color. Remove from the heat and immediately stir in the cream to stop the browning. Stir vigorously until mostly smooth; small flecks are fine. Cool for about 30 minutes.
- Beat the room-temperature cup of butter with the frosting salt and vanilla on medium-high speed for about 1 minute, until creamy. Beat in half the powdered sugar, beginning on low speed. Add the cooled brown butter mixture and remaining sugar, then beat for about 2 minutes, until fluffy.
- Spread over the completely cool cake. Finish with optional flaky salt and sprinkles.
Notes
The frosting uses two separate butter portions: 1/4 cup browned with milk powder and 1 cup kept at room temperature.
Stir the milk powder continuously while browning and have the cream ready to add off the heat.
