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.

Mix flour with sugar well.,______,Boil until thickened over low heat, stirring constantly, or cook in a double boiler.,When done, add vanilla and oleo.,Put a layer of vanilla wafers in an ovenproof bowl.,Add a layer of strawberries and another layer of vanilla wafers.,Pour pudding over all.
Add sweet milk and 3 egg yolks; beat the egg yolks just a little.