Heat the olive oil in a large, deep skillet or Dutch oven over medium heat. Add the chopped onion and cook for 5 to 7 minutes, stirring occasionally, until the onions are soft and translucent.

Stir in the minced garlic and cook for 1 minute until fragrant, taking care not to burn the garlic.

Add the ground turkey to the skillet. Break up the meat with a wooden spoon and cook until it is fully browned and no pink remains (6 to 8 minutes). If using non-lean turkey, carefully drain any excess grease from the skillet before proceeding.

Sprinkle the browned turkey with the salt, black pepper, Italian seasoning, dried oregano, and red pepper flakes (if using). Stir well to ensure the spices evenly coat the turkey.

Add the diced zucchini to the skillet. Stir everything together and cook for 5 to 8 minutes, stirring occasionally, until the zucchini begins to soften slightly but still holds its shape.

Pour in the can of crushed tomatoes, stirring to combine them with the turkey mixture. Bring the mixture to a gentle simmer. Once simmering, reduce the heat to low, cover the skillet loosely, and let the mixture cook for 5 to 10 minutes. This allows the flavors to meld and the zucchini to finish cooking until it is tender-crisp.

Remove the skillet from the heat. Stir in half of the Parmesan cheese if you prefer it mixed throughout the dish. Taste the mixture and adjust the salt and pepper as needed.

Ladle the Simple Ground Turkey and Zucchini Skillet into bowls. Garnish each serving with the remaining fresh Parmesan cheese and a sprinkle of chopped fresh basil or parsley before serving immediately.