Preheat the oven to 400°F.
Mix the bread crumbs and milk together in a large mixing bowl and sit for at least 5 minutes.
Add the beef, pork, eggs, basil parsley, oregano, garlic powder, onion powder, salt, parmesan cheese (or nutritional yeast) to the bowl then use a wooden spoon or your (clean) hands to mix it well so no yellow streaks remain and the beef and pork are fully combined.
Use a heaping tablespoon or medium cookie scoop to form the meatballs. Wet your hands with a bit of water if they're starting to stick. Place the meatballs on a large paper towel-lined plate.
Add 3-4 tablespoons of olive oil into a heavy bottomed, oven-safe skillet, like a cast-iron skillet over medium-high heat.
When the oil is hot, place the meatballs in the pan in an even layer and sear for 2 minutes on each side (8 minutes total).
Pour the marinara sauce over the meatballs and carefully transfer the skillet to the oven and bake for 15-20 minutes in the preheated oven, or until they reach an internal temperature of 165°F.
If you're serving them with pasta, boil your favorite gluten-free pasta while they cook and serve with more sauce. You can also prep meatball subs.