1. Combine Ingredients in Slow Cooker (No-Boil Method):
- Lightly grease the insert of your 6-quart slow cooker with cooking spray or butter.
- Pour the 1 pound of uncooked cellentani pasta evenly into the bottom of the prepared slow cooker.
- Scatter the sliced pieces of butter and the cubed pieces of cream cheese over the uncooked pasta.
- Sprinkle the kosher salt and cayenne pepper over the top.
- Pour the whole milk and heavy cream into the slow cooker over all the other ingredients.
2. Stir and Initial Cook:
- Stir everything together well with a spatula, ensuring all the pasta is coated in the liquid and submerged as much as possible. Smooth the pasta into one even layer.
- Cover the slow cooker securely with its lid.
- Cook on the LOW setting for 1 to 2 hours. Your exact cook time will vary based on your specific slow cooker model and the type of pasta used.
- Important: Stir the mixture once, about halfway through the cook time (e.g., at the 45-minute mark), to prevent sticking and ensure even cooking. After stirring, smooth the pasta back into an even layer so it remains coated in the sauce.
- The pasta is ready for the next step when it is chewy but still very firm (very al dente). It should not be crunchy, but also not fully soft yet. Start checking at the 1-hour mark.
3. Stir in Cheeses and Finish:
- Once the pasta has reached that chewy, al dente stage, sprinkle the 2 cups of freshly shredded sharp cheddar cheese and the 1 cup of freshly shredded pepper jack cheese into the slow cooker.
- Stir thoroughly to combine the cheeses with the pasta and the hot liquid until everything is well mixed. The residual heat will begin to melt the cheeses immediately, creating a luscious, creamy sauce.
- Cover the slow cooker again and continue cooking on LOW for about 10 more minutes.
4. Final Stir and Serve:
- After 10 minutes, the cheeses should be completely melted into the sauce, creating the most luxurious and creamy cheese sauce.
- Give the Crockpot Mac and Cheese one final, thorough stir before serving.
- Serve hot, directly from the slow cooker or portioned into bowls. Garnish with fresh chopped parsley or chives, if desired. Enjoy the ultimate creamy mac and cheese!