16 tbsp. unsalted butter, softened
3¼ cups cake flour
1 tbsp. baking powder
½ tsp. salt
6¼ cups sugar
2 tsp. vanilla extract
1¼ cups milk
16 tbsp. salted butter
2 12-oz. cans evaporated milkMethod
1. Heat oven to 350°. Making sure all ingredients are at room temperature, grease two 9" round cake pans with 1 tbsp. unsalted butter; dust with 1½ tbsp. flour, tap out excess, and set aside. Sift flour, baking powder, and salt together; set aside. Beat remaining unsalted butter and 2½ cups sugar in a bowl with an electric mixer until fluffy. Add vanilla and eggs one at a time, beating after each addition. Add flour mixture and milk alternately in 3 batches, beating smooth after each addition. Divide batter between pans. Bake until golden, 30–35 minutes. Let cool on a rack for 10 minutes; remove cakes; let cool completely. Slice tops off cakes to level them.
2. To make icing, cook remaining sugar and salted butter in a pot over high heat, stirring constantly, until light brown, 7–8 minutes. Carefully stir in evaporated milk; reduce heat to medium-low; cook, stirring constantly, until smooth, 8–10 minutes. Cook, stirring occasionally, until icing registers 240° on a candy thermometer, about 1½ hours. Remove from heat; beat with a wooden spoon until thick, glossy, and spreadable, 20–25 minutes. (A dollop dropped on a plate should ooze only slightly.) Ice bottom layer of cake; top with second layer and ice the outside. Chill cake until set.