Spray your cooking pot with olive oil.
In a bowl, add the ground meat, breadcrumbs, egg, egg yolk, garlic, onion powder, Italian spices, and salt and pepper.
Mix the ingredients well together with your hands.
Use about 4 tablespoons of the meat mixture and form into balls.
Gently insert a piece of cheese into each of the balls.
Place the balls in the cooking pot. Pour in the marinara sauce. Cook for 30-40 minutes on medium heat.
Taste.