Set the EGG for indirect cooking at 425°F/218°C.
Using a cooking grid, bake the sweet potatoes for 50-60 minutes, or until tender.
Meanwhile, in a large bowl combine the ground pork, egg, ½ cup of cheese, breadcrumbs, parsley, sage, red pepper flakes and ½ teaspoon salt. Form the mixture into golf ball-sized meatballs, arranging them on a plate or platter.
In the Half Moon Cast Iron Griddle, warm 2 tablespoons oil. Add the meatballs in a single layer, making sure they’re not touching, and let them cook until browned and cooked through, about 10 to 12 minutes. Transfer the meatballs to a paper towel-lined plate, cover to keep warm and set aside.
Cook the pasta according to package directions. Drain, cover to keep warm and set aside.
Scoop the flesh from the sweet potatoes, place it in a food processor and pulse a few times. Slowly add the half and half and milk, processing until smooth. Set aside.
Wipe out the Half Moon Cast Iron Griddle, place it back on the EGG at 350°F/177°C and warm the butter and 2 tablespoons of oil. Add the onion and garlic and let it cook until the onion is tender, about 5 minutes. Add in the flour and cook for 1 minute. Add in the sweet potato mixture, black pepper, nutmeg, and 1 teaspoon salt and cook until the sauce is thickened and heated through, 3 to 4 minutes. If the sauce is too thick, add more milk as needed. Add in ¼ cup of cheese. Add the rigatoni, stirring until it’s heated through.
Serve the pasta topped with the meatballs and garnished with chopped parsley.