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.

Lightly spray 9"x13" baking pan with cooking spray.,Add chocolate and combine well.,Add eggs and vanilla. Stir in Sugar.,______,Pour mixture into greased pan and bake at 350 for 35 minutes.
Add flour and mix until combined. Add nuts.