Cook the macaroni following package directions. Drain in a colander and rinse with hot water. Drain well.
Generously butter the sides and bottom of a 3 1/2- to 4-quart slow cooker (I use about 2 tablespoons of butter).
Combine the macaroni with the remaining ingredients in the slow cooker and blend well. Cover the slow cooker and cook on LOW for 2 1/2 to 3 1/2 hours, stirring a few times.
If desired, spoon the cooked macaroni and cheese mixture into a baking dish, sprinkle with a little more cheese, and put under the broiler for a minute or 2, just until cheese is melted.
When the macaroni and cheese is done, feel free to spoon into a baking dish, top with a little more cheese, and put under the broiler for a minute or two for that "fresh from the oven" look.