Step 1

Place two oven racks in the upper and lower thirds of the oven. Preheat the oven to 450 degrees F. Lightly grease 2 baking sheets with cooking spray, or line with parchment paper or a silpat mat.

Step 2

In a large mixing bowl, whisk together the milk and eggs until evenly combined. Add the ground turkey, turkey sausage, breadcrumbs, cheese, parsley, salt, pepper, and garlic powder. Lightly mix with a fork or your fingers, just until combined, being careful not to compact the meat. With a scoop or spoon, scoop the meat, then shape into 1 1/2-inch meatballs. Arrange on the prepared baking sheets. (You will have about 38 meatballs total).

Step 3

Bake the meatballs for 3 minutes, remove the pans from the oven and flip the meatballs, then return the pans to the oven, switching each pan from bottom to top. Bake 3 additional minutes, then remove from the oven. The exterior of the meatballs should be lightly browned, but they will not be cooked through.

Step 4

Lightly coat a 5-quart or larger slow cooker with cooking spray. Arrange a layer of meatballs over the bottom, pour on half the sauce, then stack any remaining meatballs on top. Pour on the remaining sauce. Cover and cook on high for 2 hours or low for 4 hours, until the meatballs are cooked through and reach an internal temperature of 160 degrees F. Serve warm with pasta, on buns, over polenta, or enjoy alone as an appetizer.