Heat olive oil in a large skillet over medium heat.
Add the sliced turkey sausage to the skillet and cook for 5-7 minutes, stirring occasionally, until browned and cooked through.
Add the diced onion and minced garlic to the skillet. Cook for 2-3 minutes until the onion becomes translucent.
Add the diced red and yellow bell peppers to the skillet and cook for 4-5 minutes until they begin to soften.
Stir in the sliced zucchinis and cook for another 3 minutes.
Add the halved cherry tomatoes, dried Italian seasoning, salt, and black pepper. Stir well to combine and cook for 2 minutes until the tomatoes soften slightly.
Add the fresh baby spinach to the skillet and cook for 1-2 minutes until wilted.
Remove the skillet from heat and sprinkle the grated Parmesan cheese over the top.
Serve the turkey sausage and vegetable mixture hot, dividing evenly among four plates.