Cook the elbow macaroni according to package instructions until al dente, then drain and set aside.
In a crockpot, combine the cooked macaroni and butter; stir until melted.
Add the milk, garlic powder, onion powder, salt, and pepper to the pot and mix well.
Gradually add the cheddar and Parmesan cheese, stirring until melted.
Cover the crockpot and cook on low for 2 to 3 hours, stirring occasionally.
If desired, sprinkle breadcrumbs on top during the last 30 minutes for a crunchy topping.
Once cooked, stir well and adjust seasoning if needed.
Serve hot and enjoy your creamy mac and cheese!