Mix the meatballs: In a bowl, combine ground turkey, breadcrumbs, egg, grated onion, garlic, parsley, Italian seasoning, smoked paprika, salt, pepper, and red pepper flakes. Stir gently until just combined.
Don’t overmix.
Form the balls: With damp hands, roll the mixture into 16–20 small meatballs (about 1 to 1.5 inches wide). Place on a plate.
Brown the meatballs: Heat olive oil in a large nonstick skillet over medium heat. Add meatballs in a single layer.
Cook 5–7 minutes, turning occasionally, until browned on most sides. Transfer to a plate. They don’t need to be fully cooked yet.
Sauté the vegetables: In the same skillet, add onion, bell pepper, and zucchini.
Cook 4–5 minutes until softened. Add garlic and cook 30 seconds until fragrant.
Build the sauce: Stir in crushed tomatoes, chicken broth, Italian seasoning, and oregano. Season with a pinch of salt and pepper.
Bring to a gentle simmer.
Simmer the meatballs: Nestle the meatballs into the sauce. Cover and simmer on low for 10–12 minutes, or until the meatballs reach 165°F (74°C) internally.
Finish with greens: Stir in spinach and cook 1–2 minutes until wilted. Taste and adjust seasoning.
If you like brightness, squeeze in a little lemon.
Serve: Garnish with fresh basil or parsley. Enjoy as is, or serve over cauliflower rice, zucchini noodles, or a small portion of whole grain pasta.