This cake must be served ice cold. If you do not have a rimmed platter large enough to hold this cake, then cut the cake in half and serve it on two platters.

Cake
9 egg yolks
2 cups granulated sugar
1 teaspoon vanilla extract
2 cups flour
1/2 cup milk mixed with 1 tablespoon baking powder
9 egg whites

Butter a 13 x 9-inch glass baking pan. Set oven rack in the center of the oven and preheat oven to 350 degrees F.

Beat yolks and sugar until thick and pale, about 1 minute. Add vanilla extract. Add flour alternately with milk mixture. Beat egg whites to stiff peaks. Fold about one-third of the whites into the batter to lighten it, then fold in all the egg whites until completely blended. Pour batter into the prepared baking pan. Bake 30 to 35 minutes. Cool on a rack in the pan. When cool, invert onto a large serving platter with a rim.

Three-Milk Filling
3 egg yolks
2 cups cream (or combination of 1 cup cream
    and 1 cup sour cream)
1 (5 ounce) can evaporated milk
1 (14 ounce) can sweetened condensed milk
1 teaspoon vanilla extract
1 tablespoon rum or favorite liqueur

Beat yolks well. Bring 1 cup of the cream to a boil. While beating, slowly pour cream into the yolks and continue beating until foamy and cooled. Add remaining cream and evaporated and condensed milks and beat thoroughly. Mixture will not peak. Add vanilla extract and rum.

Swirl Frosting
1/2 cup water
1 cup light corn syrup
1 1/2 cups granulated sugar
3 egg whites

Bring water, corn syrup and sugar to a boil over medium-high heat. Cook until it's a clear syrup that can spin a thread (230 degrees F to 234 degrees F). It sugar browns, it will become too caramelized and frosting will be stiff.

Meanwhile, beat egg whites until stiff. Still beating, add hot sugar syrup in a slow stream; continue beating about 5 minutes or until glossy, fluffy and stiffly peaked and somewhat cooled.

When cake has cooled, punch holes in it with the end of a wooden spoon. Slowly pour the filling over the cake so it can absorb all the filling. Swirl frosting on sides and top of cake in big strokes. Refrigerate at least 3 hours or overnight.