I don't have a sponge cake recipe from a box, but I can share a recipe that was posted for public use on TLC of the Cake Bosss Sponge cake recipe. Here you go
Cake Boss Sponge Cake
4 lg eggs at room temp
2 c white granulated sugar
1 tsp vanilla extract
1 c whole milk
1/4 c unsalted or lightly salted butter
get recipes @ goboldwithbutter.com
2 c all purpose flour
2 tsp baking powder
1/4 tsp salt (use 3/8 tsp if using unsalted butter)
Beat eggs in large mixing bowl (with paddle attachment if possible) for 4 minutes. Do not shorten the time.
Add sugar and continue beating for another 4 - 5 minutes until light and fluffy. Add vanilla and stir on low just until combined.
In a separate, sift together dry ingredients. Add to eggs and sugar on low speed just until combined.
In a saucepan (or microwave) heat milk and butter just until the butter is melted. Add to batter, beat just until combined.
Pour into two greased and floured 8" pans.
Bake at 325 about 33 - 35 mins or until the middle springs back when touched, or a toothpick inserted in the center comes out clean.
Remove from oven and let stand in pans for 10 mins. Then turn out onto a wire cooling rack and cool completely before frosting.