Preheat oven to 350 degrees F. In an 8-inch square baking pan stir together flour, brown sugar, baking soda, and salt. Stir in bananas, melted butter, milk, and vinegar just until combined, stirring to corners of pan. Sprinkle with remaining ingredients.
Bake 30 to 35 minutes or until a toothpick comes out clean (center may dip slightly). Cool in pan on a wire rack.