Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking dish.
In a large bowl, mix together the broccoli, cheddar cheese, mozzarella cheese, Parmesan cheese, mayonnaise, garlic powder, onion powder, and black pepper.
Spread the mixture into the prepared baking dish.
Sprinkle the top with the bread crumbs.
Bake in preheated oven for 25 minutes, or until cheese is melted and bubbly.
Let cool for 5 minutes before serving.
Interesting Facts
Broccoli is a member of the cabbage family and is a great source of vitamins A and C.
Cheese is a great source of calcium and protein.
Garlic powder and onion powder are great flavor enhancers.