In a large bowl, combine the ground Italian sausage, ground beef, egg, red pepper flakes, oregano, parsley, minced garlic, and bread crumbs. I like to use my gloved hands to make sure I have effectively combined all ingredients, but this can be done with a wooden spoon.
Next, fold mini pepperonis into the meat mixture. Use as little or as much as you’d like. We think of this as a “meat lovers pizza" meatball and load up on the pepperoni.
Shape the ground beef mixture into golf ball-sized balls. Use your finger to poke a hole in the center of the meatball and put a mozzarella pearl inside then seal the meat over the cheese. For this step, we used 1 mozzarella pearl. Add an additional pearl for extra cheesiness.
Pour one cup of marinara sauce into the slow cooker. Add meatballs; it is ok to stack them if need be.
Top with remaining marinara sauce and sprinkle extra mini pepperoni, mozzarella pearls, and a pinch of parsley over the meatballs.
Cover and cook on LOW for 4 hours. Top with parmesan cheese and serve with spaghetti. Enjoy!
Notes
Can I use a different kind of meat?Sure thing! Ground turkey and/or ground chicken make perfect substitutions for the beef and sausage. The taste will still be yummy!Can I make these ahead of time?Absolutely! These meatballs can be made ahead of time and frozen for later use. They are also prep-friendly, meaning you can assemble and store them in a Ziploc bag to cook another day.How can I make these spicy?Consider adding chopped jalapenos and extra red pepper flakes during the mixing process.