In a medium bowl, using your hands, combine the ground beef, half of the onion, egg Parmesan, oats, Dijon, paprika and salt. Once the mixture is evenly distributed, form small 1 inch meatballs.
Press a 1/2" cube of the cheese into the center of each meatball and roll the meatball, so the cheese is completely covered with meat mixture.
Once all of the meatballs are formed, heat the olive oil over medium-high heat in a large skillet. Arrange the meatballs in the skillet and cook for 4-5 minutes, rotating every minute so each side is browned. Add the pasta sauce to the skillet and simmer for 5 minutes.