Preheat the oven to 350 degrees. While the oven is preheating, cook the ground beef in a pan.
To prepare zucchini, slice them in half lengthwise, then use a spoon to scoop out most of the seedy center. Arrange them on a baking sheet.
When ground beef is cooked, drain and cool for a few minutes. Combine the shredded parmesan, romano, and asiago cheese blend, garlic and herb seasoning, and tomato sauce with the meat.
Spoon the meat mixture into the zucchini.
Bake for 15-20 minutes until mostly tender. Top with mozzarella cheese and pepperoni minis. Bake for another 5-10 minutes until cheese is melted and zucchini is tender.
Cool and serve.