Mom's Sponge Cake

Step 1
Preheat the oven to 350 degrees F (175 degrees C). Grease and flour a 9×13-inch baking pan.

Step 2
Beat eggs in a stand mixer fitted with the whisk attachment on high speed until thick and lemon-colored, about 3 minutes. Gradually add sugar, beating until mixture is thick, about 5 minutes. Fold flour, baking powder, and salt into the batter by hand.

Step 3
Microwave milk in a microwave-safe bowl until it begins to bubble, about 1 minute. Add butter and stir until melted. Stir in vanilla.

Step 4
Pour hot milk mixture into the batter; blend on low speed until well combined and smooth. Pour into the prepared pan.

Step 5
Bake in the preheated oven until a toothpick inserted in the center comes out clean, 25 to 30 minutes.