Preheat the oven to 375°F (190°C). Cut the zucchini in half lengthwise and scoop out the seeds to create boats.

In a skillet over medium heat, cook the ground beef until browned. Drain excess fat.

Add diced onion and minced garlic to the skillet and sauté until the onion is translucent.

Stir in tomato sauce, Italian seasoning, salt, and pepper. Cook for another 5 minutes.

Remove from heat and mix in half of the shredded cheese.

Place the zucchini halves in a baking dish and fill each with the meat mixture.

Top with the remaining shredded cheese.

Cover the baking dish with foil and bake for 20 minutes. Remove the foil and bake for an additional 5 minutes, or until the cheese is bubbly and golden.