Given the task definition and input, reply with output. In this task, you will be presented with the directions of a recipe separated by "," and have to fill in the "___" which is a step that is missing from the recipe.

Beat shortening at medium speed with electric mixer until fluffy.,Gradually add sugar, beating well.,Add egg, vanilla and butter flavoring, beating until blended.,Combine flour and soda; add to shortening mixture alternately with bananas, beginning and ending with flour mixture.,Spoon batter into greased muffin pans, filling 2/3rds full.,______,Yields 15 muffins.
Bake at 350 for 20 to 25 minutes.