Spray a 5-6-quart slow cooker with non-stick spray. Add the dry pasta to the slow cooker. Evenly distribute the cubed butter over the pasta.

To the crockpot add cheddar cheese soup, half and half, evaporated milk, 2 cups shredded cheddar cheese, monterey jack cheese, sour cream, salt, pepper, and garlic powder. Stir to combine and evenly cover the pasta.

Cover and cook on low for 1 ½ to 2 ½ hours. After the first 30 minutes stir the macaroni and check on the pasta. Cover and continue to check the macaroni every 30 minutes, until the pasta has become tender and the cheese sauce is thick and creamy.

Add the remaining ½ cup cheddar cheese to the top of the macaroni, turn the slow cooker off and cover, let the cheese melt over the top for about 8-10 minutes. Serve fresh with chopped parsley.