My sister and I came up with this one day. I had just shown her a tres leches recipe, and because red velvet cake is her all-time favorite, she said that she thought a red velvet sponge cake would be delicious. So I patched a few recipes together and we made the cake together.
Grease and flour a 9X13 inch pan. Preheat your oven to 350 degrees.
In a large bowl, cream together butter and sugar until light. Add eggs one at a time, beating after each addition. Add vanilla, beat until smooth.
In a medium bowl, combine the flour, cocoa, baking powder and salt. In a smaller bowl, combine the buttermilk and the red food coloring.
Add about 1/3 of the flour mixture to the creamed butter/sugar mixture, stir to combine. Add about 1/3 of the buttermilk to that, stirring to combine. Continue alternating between adding 1/3 of the flour and buttermilk to the butter/sugar mixture until everything has been mixed together. Stir in the tablespoon of vinegar, mix batter well to remove lumps.
Pour cake batter into the prepared pan and bake for 35-40 minutes or until the cake is firm to the touch. Remove cake from oven, turn out onto rimmed platter and let cool.
Once the cake has cooled, combine the can of condensed milk (13.5 oz), the evaporated milk (13.5 oz) and the cream in a bowl. Gradually pour the entire mixture into the cake, making sure to get all of the edges. Let the cake soak for about 30 minutes.
Take the pint of very cold cream and pour into a small bowl. Add three tablespoons of sugar to the cream and beat with a mixer on high speed until thick and spreadable, about 45 seconds. Top the cake with the whipped cream.
Note: If you have leftover cake, it is best stored in the refrigerator.