Combine dry macaroni noodles, evaporated milk and milk in the crockpot.
Add cubed cream cheese and butter.
Stir in shredded cheese and garlic powder, salt, pepper, and mustard powder.
Turn to high and cook for 1 hour.
After 1 hour, stir to combine and turn the crockpot to low.
Continue to cook another 1 ½ to 2 ½ hours on LOW, depending on how hot your crockpot gets.
Let cool slightly and serve. Cheese sauce will thicken as it cools.