Preheat oven to 475 F and line 2 baking sheets with parchment paper.
Heat olive oil in a large pan over medium-high heat until shimmering. Add onions and cook until soft, 6-7 minutes. Add minced garlic, dried oregano, and crushed pepper flakes and cook until garlic is fragrant, about 1 minute.
Place onions/garlic mixture in a large bowl. Add grated parmesan and combine using your hands. Add Italian sausage, eggs, ground beef, and salt and knead until ingredients are well incorporated.
Form into 40 - 2 1/2" inch meatballs. Place meatballs on the prepared baking sheets. Bake in preheated oven for 17-19 minutes. The internal temp of your meatballs should be 160 F.
Meanwhile, heat pasta sauce in a large pan. Serve the meatballs warm, over your favorite low carb pasta with sauce on top. Enjoy!
Nutritional information is based on 1 serving if you make 40 meatballs, which would be 4 meatballs per serving: