In a large skillet, heat the olive oil over medium heat. Add the diced onion and sauté for about 3-4 minutes until it becomes translucent.
Stir in the minced garlic, cooking for an additional 1 minute until fragrant.
Add the ground turkey to the skillet, breaking it apart with a spatula. Cook until browned and no longer pink, about 5-7 minutes.
Incorporate the diced bell pepper and zucchini, cooking for another 5 minutes until the vegetables begin to soften.
Pour in the diced tomatoes with their juices, and sprinkle in the Italian seasoning and red pepper flakes. Stir to combine and bring the mixture to a simmer.
Once simmering, add the chopped spinach (or kale) and stir until wilted, about 2 minutes.
Season the mixture with salt and pepper to taste.
Reduce the heat to low and sprinkle the mozzarella cheese on top. Cover the skillet with a lid and let it cook for a few more minutes until the cheese is melted and bubbly.
Remove from heat and garnish with fresh basil leaves before serving.
Notes
Serve hot directly from the pan or plate individually with additional basil and cheese. Pair with crusty bread or quinoa.