01 -
Melt butter in a skillet over medium heat. Add onion and cook for 5 minutes until softened. Stir in garlic and cook for 1 minute more. Let cool completely.
02 -
In a large bowl, whisk together egg, half and half, Worcestershire sauce, oregano, salt, pepper, and red pepper flakes. Stir in breadcrumbs, Parmesan, parsley, and cooled onion mixture.
03 -
Add ground turkey and turkey sausage to the bowl. Gently mix until just combined without overworking to avoid tough texture.
04 -
Form into 1.5-inch balls. If sticky, roll once, flash freeze for 3 to 5 minutes, then roll again until smooth.
05 -
Preheat oven to 350°F. Line a baking sheet with parchment paper.
06 -
Arrange meatballs on prepared sheet and bake for 22 minutes. Raise temperature to 450°F and bake for 5 more minutes.
07 -
Let meatballs rest for 5 minutes before serving to allow juices to redistribute.
08 -
Place rolled meatballs in greased slow cooker. Add 32 oz. marinara sauce and 2 cups mozzarella cheese. Cook on high for 3 to 4 hours or low for 6 to 7 hours.
09 -
In a 9x13 baking dish, add marinara and meatballs. Cover with foil and bake at 375°F for 30 minutes. Remove foil, top with cheese, and bake 15 more minutes. Broil 1 to 2 minutes to brown top if desired.