In a small bowl, whisk the eggs with the milk and sour cream or ricotta; add the breadcrumbs and stir to combine. Let soak for 20 minutes. 

While that soaks, heat butter and olive oil in a skillet until the butter is melted. Add the shallots and cook until softened, 3-5 minutes, then add the garlic and cook for an additional minute. Remove from the heat and set aside. 

In a large bowl, place ground beef and pork along with parmesan, parsley, soaked breadcrumbs, Italian seasoning and the shallot mixture, along with a couple of large pinches of salt and pepper. Use your hands to mix until well incorporated. 

Place the meatball mixture in the fridge to chill for 20 minutes. This helps with portioning. 

While the mixture rests, take a small amount (about 1 tablespoon) of the mixture and pat it into a small patty; sear it in a skillet. Taste the patty and add more salt and pepper to the meatball mix if needed.

Using a cookie scoop (about 2 tablespoons), portion all of the meat onto a lined or sprayed baking sheet. Once portioned, coat your palms in olive oil, then take each meatball and roll it into a ball with your palms. Try not to squeeze the mix too tightly; you don’t want the meatballs to be dense. Once rolled, lightly spray the meatballs with cooking spray. This will help them brown nicely.

Preheat your air fryer to 400°F for 5 minutes.

Working in batches as necessary depending on the size of your air fryer, place the meatballs into the air fryer basket.

Cook at 400°F for 10 minutes, flipping the meatballs halfway through.

Add to pasta sauce, use in your recipe, or let cool and freeze for later.