Pastel Layer Cake w/Swiss Meringue Buttercream

By MarieR

Ingredients

• Cake:
• •3 1/2 sticks unsalted butter, room temperature, plus more for pans and parchment
• •6 1/2 cups sifted cake flour (not self-rising), plus more for pans and parchment
• •3 tablespoons baking powder
• •Salt
• •2 1/4 cups whole milk
• •2 tablespoons pure vanilla extract
• •2 1/2 cups sugar
• •10 large egg whites
• •Gel-paste food coloring (nycake.com)
• •Swiss Meringue Buttercream
• About 10 cups (enough for 7 dozen Number-Themed Mini Birthday Cupcakes, 1 "Who's Counting?" Birthday Cake, or 1 Pastel Layer Cake)
• •2 1/4 cups sugar
• •10 large egg whites, room temperature
• •Pinch of salt
• •8 sticks unsalted butter, room temperature, cut into small pieces
• •1 tablespoon pure vanilla extract

Preparation

Step 1

Cake:

1.Preheat oven to 350 degrees. Butter five 8-inch round cake pans, and line with parchment (you may need to bake in batches). Butter parchment, and dust with flour, tapping out excess. Sift flour, baking powder, and 1/2 teaspoon salt into a large bowl. Combine milk and vanilla. Beat butter with a mixer on medium speed until very smooth. With machine running, gradually add sugar, and beat until pale and fluffy, about 3 minutes.

2.Reduce speed to low, and add flour mixture in 3 additions, alternating with milk mixture, beginning and ending with flour. Beat until just combined; do not overmix.

3.Beat egg whites in a clean mixer bowl on medium speed until stiff (but not dry) peaks form, about 3 minutes. Gently fold egg-white mixture into batter in 3 additions.

4.Divide batter among 5 bowls, and tint each with food coloring to create different pastel shades. Spread each into a prepared pan. Bake until a toothpick inserted into the centers comes out clean, 18 to 20 minutes. Let cool completely in pans on wire racks.

5.Loosen edges of cake with a small metal spatula or paring knife; invert onto racks. Discard parchment. Reinvert cakes, top side up. Let cool completely.

6.Trim top of each cake to make surface even. Spread 1 cup buttercream onto top of 1 cake. Top with another cake. Repeat, spreading 1 cup buttercream between each layer. Frost cake with 1 1/2 cups buttercream. Refrigerate for 30 minutes. Frost cake with 2 cups buttercream.

Buttercream:

•Heat sugar, egg whites, and salt in a heatproof mixer bowl set over a pan of simmering water, whisking, until sugar dissolves, about 2 minutes.

•Return bowl to mixer, and whisk, gradually increasing speed from low to medium-high, until stiff, glossy peaks form, about 10 minutes. Reduce speed to medium. Add butter, a few pieces at a time, whisking well after each addition. Whisk in vanilla. Switch to a paddle attachment. Beat until air bubbles are gone, 2 to 3 minutes more.

•Beat in food coloring, 1 drop at a time, until desired color is achieved. (If making more than 1 color, divide buttercream and work in batches.)

•Bring to room temperature before using, and beat on low speed until smooth