Cook Pasta
Boil elbow macaroni in salted water for 4–5 minutes only (just until barely tender; it will finish cooking in the crock pot). Drain well.
Prepare Crock Pot
Grease the inside of your slow cooker with butter or non-stick spray to prevent sticking.
Combine Ingredients
In the crock pot, add the drained pasta, 3 cups of shredded cheddar, milk, evaporated milk, melted butter, cream cheese, salt, pepper, and optional spices. Stir well to combine.
Slow Cook
Cover and cook on low for 2–3 hours, stirring halfway through, until the cheese is fully melted and the sauce is creamy.
Add Remaining Cheese
About 15 minutes before serving, sprinkle the remaining 1 cup of cheddar cheese on top. Cover and let melt.
Serve
Stir before serving for a smooth texture. Serve warm.