Step 1

In a large crockpot add the pasta, cheese, garlic, onion, cream cheese, 4 tbsp of the butter, nutmeg, salt and pepper.Pour the milk over the top of all the ingredients and stir to roughly combine

Step 2

Pasta should be mostly submerged under the milk

Step 3

Cook on low for 2 hours.After 2 hours, remove lid and stir all ingredients together

Step 4

Arrange mushroom caps upside down all over the top of the mac and cheese.Fill each stem hole with a pat of butter from the reserved butter.Close the crock pot and cook for 1 hour.Top dish with chives and flat leaf parsley and serve hot.