Ingredients

Makes 1 quarter sheet pan cake

　　115 g butter, at room temperature [8 tablespoons (1 stick)]

　　300 g sugar (1 1/2 cups)

　　3 eggs

　　110 g buttermilk (1/2 cup)

　　40 g grapeseed oil (1/4 cup)

　　4 g vanilla extract (1 teaspoon)

　　1/4 recipe Fudge Sauce (page 136) [38 g (3 tablespoons)]

　　155 g cake flour (1 1/4 cups)

　　70 g cocoa powder, preferably Valrhona (1/2 cup)

　　6 g baking powder (1 1/2 teaspoons)

　　6 g kosher salt (1 1/2 teaspoons)

　　Pam or other nonstick cooking spray (optional)

　　

Step 1

Heat the oven to 350°F.

　　

Step 2

Combine the butter and sugar in the bowl of a stand mixer fitted with the paddle attachment and cream together on medium-high for 2 to 3 minutes. Scrape down the sides of the bowl, add the eggs, and mix on medium-high for 2 to 3 minutes. Scrape down the sides of the bowl once more.

　　

Step 3

On low speed, stream in the buttermilk, oil, and vanilla. Increase the mixer speed to medium-high and paddle for 3 to 5 minutes, until the mixture is practically white, twice the size of your original fluffy butter-and-sugar mixture, and completely homogenous. There should be no streaks of fat or liquid. Stop the mixer and scrape down the sides of the bowl.

　　

Step 4

Add the fudge sauce and mix on low speed until fully incorporated. Scrape down the sides of the bowl.

　　

Step 5

With a spatula, stir the flour, cocoa powder, baking powder, and salt together in a medium bowl. On very low speed, add the dry ingredients and mix for 45 to 60 seconds, just until your batter comes together. Scrape down the sides of the bowl, and mix on low speed for another 45 seconds to ensure that any little lumps of cocoa powder and cake flour are incorporated.

　　

Step 6

Pam-spray a quarter sheet pan and line it with parchment, or just line the pan with a Silpat. Using a spatula, spread the cake batter in an even layer in the pan. Bake for 30 to 35 minutes. The cake will rise and puff, doubling in size, but will remain slightly buttery and dense. At 30 minutes, gently poke the edge of the cake with your finger: the cake should bounce back slightly and the center should no longer be jiggly. Leave the cake in the oven for an extra 3 to 5 minutes if it doesn’t pass these tests.

　　

Step 7

Take the cake out of the oven and cool on a wire rack or, in a pinch, in the fridge or freezer (don’t worry, it’s not cheating). The cooled cake can be stored, wrapped in plastic wrap, for up to 5 days.

　　Reprinted with permission from Momofuku Milk Bar by Christina Tosi with Courtney McBroom. Copyright © 2011 by MomoMilk, LLC. Published by Clarkson Potter, a division of Random House, Inc. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.Christina Tosi is the chef and owner of Momofuku Milk Bar, called "one of the most exciting bakeries in the country" by Bon Appètit. As founder of the desserts programs at Momofuku, including Noodle Bar, Ssäat;m Bar, Ko and Má Pêche, Christina was most recently shortlisted for a James Beard Foundation Rising Star Chef Award. Christina and her confections have appeared on The Martha Stewart Show and Live! with Regis and Kelly, among others. She lives in Brooklyn, New York, with her three dogs and eats an unconscionable amount of raw cookie dough every day.