This tried-and-true recipe is adapted from the one on the Nilla Wafers box.
1/3 cup flour
3/4 cup sugar, divided
3 eggs separated
2 cups milk
1/2 teaspoon vanilla extract
30 Nilla Wafers, divided
5 medium-ripe bananas, sliced (about 3 1/2 cups)
1. Preheat oven to 350 degrees. Mix flour, 1/2 cup of the sugar and salt in the top of a double boiler over boiling water. Whisk in 3 egg yolks and milk. Cook, uncovered, stirring constantly, until custard has thickened, 10 to 12 minutes. Remove from heat. Stir in vanilla extract.
2. In the bottom of a 1 1/2-quart baking dish, spread a small amount of custard. Cover evenly with 10 wafers, then with 1/3 of the sliced bananas, then with 1/3 of remaining custard. Make 2 more layers: 10 wafers, 1/3 of the bananas, 1/3 of the custard.
3. With an electric mixer, beat egg whites on high until soft peaks form. Gradually add remaining 1/4 cup sugar and continue beating until stiff peaks form. Spoon egg whites over custard, spreading evenly so that no custard is visible. Use a spatula to draw whites into attractive peaks. Bake until lightly browned, 15 to 20 minutes. Cool slightly and serve.
Makes 12 servings.