Combine flour and salt in a medium saucepan. Gradually stir in milks and yolks, and cook over medium heat, stirring constantly, 8 minutes or until thickened. Remove from heat; stir in vanilla.
Arrange 1 cup banana slices in bottom of a 2-quart baking dish. Spoon one-third pudding mixture over bananas; top with 15 vanilla wafers. Repeat layers twice, ending with pudding; arrange remaining 15 wafers around inside edge of dish. Gently push wafers into pudding.
Beat egg whites at high speed with an electric mixer until foamy. Add sugar, 1 tablespoon at a time, beating until stiff peaks form and sugar dissolves (2 to 4 minutes). Spread meringue over pudding, sealing to edge of dish.
Bake at 325° for 25 minutes or until golden. Let cool at least 30 minutes.