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 Wesson oil, margarine, sugar and eggs together.,Sift the flour, soda, baking powder and cream of tartar together and add to first mixture.,Beat well and add vanilla.,Drop by teaspoon on ungreased cookie sheet.,Bake in 325,______
oven for 15 to 20 minutes until brown.