Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper and lightly grease with cooking spray or olive oil.
If using fresh broccoli, blanch it in boiling water for 2-3 minutes until tender, then finely chop it. If using frozen broccoli, thaw and drain well, then chop finely.
In a large mixing bowl, combine the chopped broccoli, shredded cheddar cheese, grated Parmesan cheese, breadcrumbs, beaten eggs, garlic powder, onion powder, salt, and black pepper. Mix well until all ingredients are thoroughly combined.
Scoop about 1 tablespoon of the mixture and form it into a ball. Place each ball onto the prepared baking sheet. Repeat with the remaining mixture, spacing the balls about 1 inch apart.
Place the baking sheet in the preheated oven and bake for 20-25 minutes, or until the balls are golden brown and crispy on the outside. Turn the balls halfway through baking to ensure even cooking.
Once baked, remove the broccoli cheese balls from the oven and let them cool slightly before serving. They are best enjoyed warm and can be served with your favorite dipping sauce.