I do several things with Mac & Cheese. I add ham or bacon, or sarted bell pepper and onion. Regardless of what I do I start with a butter and flour roux, add cream and milk, and Velvetta, American and a little Cheddar cheeses, salt and pepper, until it is the consistency and flavor I like. Stir in cooked, drained elbow macaroni and pour in a greased baking 8x10 or 9x12 pan. I grate or crush toasted croutons on the top. Bake 350 until the top bubbles and starts to brown. 25-30 minutes. Maybe longer, maybe less. I usually start checking it about 20 minutes.