Preheat oven to 350°F Generously butter a 13 x 9-inch baking dish or a 10”cake pan.
CAKE: Beat 3/4 cup sugar and the egg yolks until light and fluffy, about 5 minutes. Fold in the milk, vanilla, flour and baking powder. Beat the egg whites to soft peaks, adding the cream of tartar after 20 seconds. Gradually add the remaining 1/4 cup sugar and continue beating until the whites are glossy and firm, but not dry. Gently fold the whites into the yolk mixture. Pour this batter into the buttered baking dish. Bake the cake until it feels firm and an inserted toothpick comes out clean, about 30-45 minutes. Let the cake cool completely in baking dish. Pierce the cake all over with a fork, taking care to not tear it up.
MILK SYRUP: Combine the evaporated milk, sweetened condensed milk, cream, vanilla and rum in a mixing bowl. Whisk until well blended. Pour the syrup over the cake, spooning the overflow back on top, until it is all absorbed.
When ready to serve, cut a slice and plate it.
Top with a dollop of freshly whipped cream or a side of ice cream, dust cake with fresh cocoa powder and place a slice or two of fresh mango, caramelized banana, berries, kiwi and mandarin oranges, or whatever fruit you prefer on the side.