For the cake
- 1 1/2 c. (3 sticks) butter, softened
- 2 1/4 c. granulated sugar
- 4 large eggs
- 1 tbsp. pure vanilla extract
- 3 c. all-purpose flour
- 1/4 c.cornstarch
- 2 tsp.baking powder
- 1 tsp.kosher salt
- 1 1/4 c.milk
- 1 c. mini chocolate chips
- 9 Chips Ahoy cookies, crushed
- 2 c. (4 sticks) butter, softened
- 1/2 tsp.kosher salt
- 1 (14-oz.) can sweetened condensed milk
- 2 c.powdered sugar
- Chips Ahoy cookies
- Make cake: Preheat oven to 350°. Line three 8" cake pans with parchment paper.
- In a large bowl using hand mixer (or in the bowl of a stand mixer), beat together butter and sugar until light and fluffy. Add eggs one at a time, beating well after each addition. Add vanilla and mix until combined.
- In another large bowl, whisk together flour, cornstarch, baking powder, and salt. Add half of the dry ingredients to the wet ingredients, beating until just combined. Pour in milk and mix until fully incorporated. Add remaining dry ingredients and stir until just combined. Fold in mini chocolate chips and crushed cookies.
- Divide batter evenly between prepared cake pans. Bake until slightly golden on top and a toothpick inserted into the middle comes out clean, about 38 to 40 minutes. Let cool completely.
- Meanwhile, make frosting: In a large bowl using the hand mixer, or in a standing mixer with the paddle attachment, beat butter and salt until light, fluffy, and lightened in color, 5 to 7 minutes. Slowly beat in sweetened condensed milk until fully incorporated, then beat in powdered sugar until smooth.
- To assemble cake: Use a serrated knife to level tops of cakes. Place a small spoonful of frosting in the center of your serving dish to secure bottom cake. Cut four 3" wide strips of parchment paper, and place in a square on your serving dish.
- Frost crumb coat: Place first layer of cake in the center of your serving dish. Top with 1 cup buttercream and smooth into an even layer. Top with second cake, frost with another cup of buttercream, then top with final cake and frost with one more cup buttercream. Smooth out excess frosting along sides of cake until completely coated, adding more fresh buttercream if needed. Refrigerate 30 minutes.
- When crumb coat has hardened, continue frosting cake with a thick layer of buttercream, reserving 1/2 cup for piping, if desired.
- Decorate cake with cookies and serve.