The Cheesiest Crock Pot Mac & Cheese, Cooking Time: 4 Hours, Directions: 1) Spray your crockpot lightly with cooking spray. Layer 1/3 of the macaroni in bottom. Layer half of cheese, butter, salt & pepper. Repeat, ending with last 1/3 of macaroni on top. Pour milk over mixture. 2) Cook on low for about 4 hours and stir about mid-way.