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.

Preheat oven to 350F (180C).,______,Melt the butter in a saucepan over medium-low heat.,Whisk in the flour, then add the milk, salt and peppers.,Stir constantly until the mixture thickens and is smooth, 8 to 10 minutes.,Add the cheese and cook, stirring, until it melts.,In a mixing bowl, combine the macaroni and the sauce.,Stir in the tomatoes and sugar.,Transfer macaroni mixture to the baking dish.,BAke until the surface browns, 30 to 40 minutes.
Grease a 1 1/2-quart baking dish.