In the slow cooker, combine the elbow macaroni, grated sharp cheddar cheese, chopped American cheese, butter, half and half, Dijon mustard, onion powder, salt, black pepper, and paprika. Stir well to combine all the ingredients.
Cover the slow cooker and cook on Low for 2 hours, stirring every 30 minutes to ensure even cooking and to prevent the pasta from sticking to the bottom.
After 1 ½ hours, check the doneness of the pasta. If the pasta is fork-tender and the cheese has melted, the mac and cheese is done. If the pasta is still too firm, continue cooking for a bit longer, checking every 15 minutes until it reaches the desired tenderness.
If the sauce appears too thick, stir in a few tablespoons of milk to help loosen it to your desired consistency.
Once cooked, serve the mac and cheese immediately, sprinkle sliced fresh green onions.
Notes
Adjust the cooking time as needed based on your specific slow cooker model and the desired tenderness of the pasta.Grease the slow cooker crock to prevent sticking. Use cooking spray or butter to coat the insert lightly. This will help avoid the cheesy goodness from sticking to the sides and bottom of the pot.Let it rest before serving. Letting it rest for a few minutes allows the flavors to meld together beautifully, resulting in a more delicious dish. This short resting period will let the sauce thicken slightly, creating a creamy texture everyone loves.Any leftovers can be stored in an airtight container in the refrigerator for up to 3 days.