Grease 2 cookie sheets. In a large bowl cream the butter and sugar with an electric mixer at medium speed. Add the egg, vanilla, and bananas, beating until well blended. Add the flour, cinnamon, baking soda, and salt, and mix until blended. Stir in the granola. Drop by the tablespoon onto the prepared cookie sheets, spacing about 2 inches apart. Bake in a 375 degrees oven for 12 minutes. Cool on a wire rack.