Heat 2 tablespoons olive oil in a large pot over medium heat. Once the oil starts to shimmer (but before it smokes), add your minced garlic. Let it cook for about 30-45 seconds until fragrant but not brown.
Pour in both cans of crushed tomatoes (I like to swirl a bit of water in each can to get all the tomato goodness out). Add the basil, oregano, salt, pepper, and red pepper flakes if using. Give everything a good stir, bring to a gentle bubble, then reduce heat to low. Let it simmer uncovered, stirring occasionally to prevent sticking. The sauce will gradually thicken as we work on the meatballs.
For the meatballs, grab your largest mixing bowl. Combine the ground chicken, breadcrumbs, Parmesan, eggs, garlic, parsley, salt, and pepper. The key here is to mix just until everything is evenly combined – overworking will make tough meatballs.
Shape the mixture into meatballs about 1½ inches in diameter (roughly golf ball size). If the mixture sticks to your hands too much, wet them slightly with cold water. Place the formed meatballs on a plate or baking sheet.
Heat 2 tablespoons olive oil in a large skillet over medium heat. Once hot, add meatballs in batches. Cook for about 3-4 minutes on each side until they’re golden brown – they won’t be fully cooked through yet, and that’s okay.
As each batch browns, transfer the meatballs directly into your simmering sauce. Once all meatballs are in, let them simmer in the sauce for another 15-20 minutes, occasionally spooning sauce over them.
Your sauce should now be rich and thick enough to coat the back of a spoon, and the meatballs should be tender and juicy. Give it a final taste and adjust the seasoning if needed – sometimes the tomatoes need a pinch more salt to really shine.
Serve hot, spooning plenty of sauce over each portion. These meatballs are fantastic over pasta, in sub rolls, or just on their own with some crusty bread to mop up the sauce.