Preheat the oven to 350 degrees F. Spray a 13x9-inch baking pan with cooking spray.
Get out and measure all of your ingredients.
Heat olive oil in a large skillet over medium heat. Add the onion, garlic and ground meat. Cook together 4 to 6 minutes, stirring often, until the onions are softened and the meat is cooked through.
In a small bowl, mix the cheeses together. Remove four heaping tablespoons of the cheese and set aside. Add the rest of the cheese to the meat mixture, along with the marinara sauce and Italian seasoning. Add salt and pepper, as desired. Mix well.
Use a small spoon to scrape out the insides of each zucchini half - the seeds and pulp. Make a valley to hold the stuffing! Pat inside of the zucchini with paper towel.
Brush lightly with olive oil.
Divide the meat mixture between the zucchinis.
Filling each one.
Put the stuffed zucchinis onto the prepared pan and sprinkle the reserved cheese on top.
Bake 30 minutes.
Or until baked through and tender.
Enjoy every bite.