How to Make It
Preheat oven to 350°.
Grease and lightly flour a 9x13-inch glass baking dish. Whisk together flour, baking powder, and salt in a large bowl. Place egg whites in a large bowl; beat with an electric mixer at high speed until soft peaks form, about 3 minutes. Set aside.
Combine 2 cups sugar, egg yolks, and vanilla in a large bowl; beat with an electric mixer at medium-high speed until pale and thick, about 3-4 minutes. With mixer running, slowly stream in half of the whole milk and then 1/2 the flour mixture. Repeat with the rest of the milk and flour mixture and mix until combined and the batter is smooth.
Gently fold the egg whites into the batter using a rubber spatula. Pour batter into prepared pan. Bake at 350° for 30-35 minutes, or until a toothpick inserted into center of cake comes out clean. Allow cake to cool in pan on a wire rack for 20 minutes.
Invert the cake onto a larger rimmed baking sheet or rimmed platter. Whisk together the sweetened condensed milk, evaporated milk, 2 cups heavy cream, and the rum flavoring until well blended. Poke small holes evenly over the entire surface of the cake using a fork or a wooden skewer; pour milk mixture slowly and evenly over cake so the syrup penetrates the cake.
Combine heavy cream and remaining 1 tablespoon sugar in a large bowl; beat with an electric mixer fitted with the whisk attachment until stiff peaks form. Spread whipped cream evenly over cake; top with strawberries, pineapple, grapes, and kiwi.