Heat olive oil in a large skillet over medium heat.
Add onion and sauté until translucent, about 5 minutes. Stir in garlic and cook for another minute.
Add ground turkey and cook until browned, breaking it up as it cooks.
Stir in crushed tomatoes, tomato paste, oregano, basil, salt, and pepper.
Reduce heat to low and let simmer for 15 to 20 minutes, stirring occasionally.
Meanwhile, spiralize the zucchini and sauté them in a separate skillet for 2-3 minutes until just tender.
Serve the Bolognese sauce over the zucchini noodles and top with parsley and Parmesan if desired.