In a large bowl, toss the broccoli with garlic, olive oil, salt, and pepper. Pour it onto the prepared pan, making sure to use a spatula to get all the excess oil and seasonings onto the pan.
8 cups broccoli florets, 2 cloves garlic, 3 tablespoons olive oil, 1 1/2 teaspoon kosher salt, 1/4 teaspoon black pepper