Toss Bananas gently with Powdered Sugar, Lemon Juice, and Rum or Kirsch;
Marinate 45 to 60 minutes, turning occasionally.
Heat Shortening slowly to 365°F.
Sift Flour, Sugar, Baking Powder, and Salt together in a bowl; Set aside.
Melt 1 tbsp. Shortening and let cool.
Drain Bananas, reserving liquid for batter.
Beat Egg Yolks until thick and lemon colored; add melted Shortening, reserved liquid, Milk, and Vanilla.
Make a well in dry ingredients; add liquid mixture and blend just until smooth.
Fold in beaten Egg Whites.
Coat Bananas with ¼ cup Flour.
Dip Bananas into batter with a slotted fork, drain excess, and deep fry without crowding until golden brown (2–3 minutes).
Drain on absorbent paper and serve immediately topped with Fruit Sauce.