Preheat the oven to 350 degrees F. Line a rimmed baking sheet with heavy-duty aluminum foil or parchment paper. If using foil, lightly spray the foil with nonstick spray.
In a small bowl, combine the bread crumbs and milk. Stir. The mixture will be very fluid at first, and will thicken as it stands. Set it aside.
In a large bowl, combine the beef and sausage. Add the eggs and soaked bread crumbs. Gently mix.
Add the cheese, Pizza Seasoning, and parsley. Stir, using your hands, or a stand mixer fitted with the blade on low speed, until thoroughly combined. (I don’t really the stand mixer this method, but it does keep your hands cleaner. Disposable gloves work well, too, for your hands' cleanliness.)
Scoop about a tablespoon from the meat mixture and make a small “patty.” Fry the patty (do not microwave even though it’s quicker) then taste and adjust any seasonings.
Using a #24 (red handle/almost 2 T) disher, a spoon, or your fingers, scoop (equal-amounts) the meat mixture, shape into meatballs and place onto the baking sheet.
Bake for 25 to 30 minutes, or until a digital thermometer reads 165 degrees F.
Remove from the oven, place onto a platter and serve warm with hefty toothpicks or a fork. Or, place the meatballs into an oven-proof baking dish. Pour marinara sauce over the top, sprinkle with shredded mozzarella and pop under the broiler just until the cheese is melted and lightly browned.
Leftovers can be kept in an airtight container for up to 5 days. Baked meatballs can be frozen in an airtight container for up to 3 months.