This is what happens when your favorite childhood dessert grows up. We created this elegant cake with milk and cookies in mind: The batter is brown sugar–tinged, for a cookie-dough-like flavor, and flecked with miniature chocolate chips— plus toffee for a caramel crunch. And the milk? A luscious créme anglaise buttercream.

Make the cake: Preheat oven to 350°F. Brush two 9-inch round cake pans with butter. Line with parchment; butter parchment. Dust with flour, tapping out any excess.

In a large bowl, whisk together cake flour, baking powder, and salt. With an electric mixer, beat butter and both sugars on high speed until light and fluffy, about 6 minutes. Add whole eggs and egg yolks, one at a time, beating well after each addition until combined. Beat in vanilla extract. With mixer on low, add flour mixture to butter mixture in three batches, alternating with butter-milk, beginning and ending with flour, and scraping down sides of bowl as needed. Stir in mini chocolate chips.

Divide batter evenly between prepared pans, smoothing tops with an offset spatula. Bake until cake tester comes out clean, about 35 minutes. Transfer pans to a wire rack to cool 10 minutes. Turn out cakes onto rack to cool completely.

Make the walnut toffee crunch: In a medium saucepan, heat butter and granulated sugar over high, stirring, until butter is melted. Continue to cook, stirring occasionally, until mixture is dark amber, 8 to 10 minutes more. Add toasted walnuts and salt, and stir to combine; transfer immediately to a baking sheet lined with a nonstick baking mat to set. Once cooled, roughly chop.

Make the buttercream: In bowl set over (not in) a saucepan of simmering water, whisk together egg whites and granulated sugar. Cook, whisking occasionally, until mixture is completely smooth when rubbed between two fingers, 3 to 5 minutes. Remove bowl from heat. With an electric mixer, whisk on low speed for 1 minute; then increase speed to medium-high and beat until stiff, glossy peaks form, 7 to 10 minutes. Reduce speed to medium-low and add butter, a few pieces at a time, until all is incorporated. Add vanilla, and then nonfat milk powder, and whisk to combine. Switch to the paddle attachment and beat on low speed about 2 minutes to remove any air bubbles.

For assembly: With a serrated knife, split each cake in half horizontally to form a total of 4 layers. Anchor bottom layer on a cake board with a dab of buttercream. Spread a generous 1 cup butter-cream evenly over cake layer, then top with one-third of walnut toffee crunch. Top with second cake layer, pressing down lightly to adhere. Repeat process, finishing with final cake layer bottom-side up. Spread a thin, even layer of buttercream over top and sides to create a crumb coat. Refrigerate about 30 minutes. Spread remaining frosting evenly over top and sides, finishing top with a decorative swirl, if desired. Using remaining mini chocolate chips, create a Swiss dot pattern around sides of cake. Refrigerate until firm, about 30 minutes. Bring to room temperature before serving.

DECORATING TIP To create a Swiss dot pattern around the sides of the cake, apply a total of five rows of mini chocolate chips: Begin with a row in the center of the cake, applying each chocolate chip approximately 1½ inches apart. Repeat a row, 1½ inches above and below the initial one. Apply the final two rows in between the top and center rows, and then between the center and bottom rows. Offset the placement of the first chip by approximately ¾ inch, centering it between two chips in the above row

Reprinted from Martha Stewart’s Cake Perfection Copyright © 2020 by Martha Stewart Living Omnimedia, LP. Published by Clarkson Potter, an imprint of the Crown Publishing/Random House, a division of Penguin Random House LLC. Photographs by Lennart Weibull.