Karen's Crockpot Mac & Cheese

16 oz Elbow Macaroni (make sure its 16oz and not 12oz)
1 Stick butter
1 quart milk
1 spoon of deli mustard to taste (optional)
Course ground black pepper to taste (optional)
1 lb of Velvetta

Boil Pasta for 4 minutues, drain. Do not rinse
Put all ingrediants into crockpot and cook on low for 3 hours. Stirring occassionally.