Cream butter and sugar. Add the vanilla, egg and bananas. Blend in flour, baking powder and salt. Stir in chocolate chips.
Spread in a greased jelly-roll pan (15x10x1 inch). Bake in a preheated oven at 350 degrees for 20 to 25 minutes.
Tip: Dust with confectioner's sugar or drizzle with a vanilla glaze. YUM!