Soak bread crumbs in milk in a small bowl for 20 minutes.

Mix beef and pork together in a large bowl. Stir onion powder, bread crumb mixture, eggs, parsley, garlic, salt, black pepper, red pepper flakes, Italian herb seasoning, and Parmesan cheese into meat mixture with a rubber spatula until combined. Cover and refrigerate for about one hour.

Using wet hands, form meat mixture into balls about 1 1/2 inches in diameter. Arrange onto prepared baking sheet.

Press the brown/sauté button and add 1 tablespoon olive oil and let heat.

Brown the meatballs on each side for approximately two minutes on each if desired. Turn off the sauté function. Add a layer of sauce to the bottom of the pot with 1/2 cup of beef broth or water. Place the lid on lock, press the Steam button and adjust the time to 12 minutes. Do an immediate release and remove from pot to cool.

Cover a baking sheet with foil and spray lightly with cooking spray.

Soak bread crumbs in milk in a small bowl for 20 minutes.

Mix beef and pork together in a large bowl. Stir onion powder, bread crumb mixture, eggs, parsley, garlic, salt, black pepper, red pepper flakes, Italian herb seasoning, and Parmesan cheese into meat mixture with a rubber spatula until combined. Cover and refrigerate for about one hour.

Preheat an oven to 425 degrees F (220 degrees C).

Using wet hands, form meat mixture into balls about 1 1/2 inches in diameter. Arrange onto prepared baking sheet.

Bake in the preheated oven until browned and cooked through, 15 to 20 minutes.