Preheat your oven to 425°F (220°C). Line a large, heavy sheet pan with parchment paper or lightly grease it with olive oil.
3 tablespoons extra-virgin olive oil
Trim the woody ends from the broccoli stems, then cut the crowns into large florets, about 2 inches each. If any stems are very thick, slice them in half lengthwise so they cook evenly. Keep the stems; they will crisp up nicely.
2 pounds broccoli crowns
Bring a large pot of well-salted water to a boil (it should taste slightly salty). Add the broccoli and cook for 3–4 minutes, until bright green and just barely tender—you should be able to pierce it with a fork, but it should not be soft.
2 pounds broccoli crowns, 1 teaspoon kosher salt
Drain the broccoli, then transfer it to a large bowl of ice water to stop the cooking. Let sit for 1–2 minutes, then drain very well. Spread the broccoli out on a clean kitchen towel or paper towels and pat completely dry for maximum crispiness.
2 pounds broccoli crowns, ice
In a large bowl, whisk together the olive oil, kosher salt, black pepper, minced garlic, garlic powder, onion powder, and smoked paprika. Add the dried broccoli and toss gently until every piece is evenly coated.
2 pounds broccoli crowns, 3 tablespoons extra-virgin olive oil, 1 teaspoon kosher salt, 1/2 teaspoon black pepper, 4 cloves garlic, 1/2 teaspoon garlic powder, 1/2 teaspoon onion powder, 1/2 teaspoon smoked paprika
Spread the seasoned broccoli out on the prepared sheet pan in a single layer, leaving space between each floret. If the pan is crowded, use a second pan to prevent steaming.
2 pounds broccoli crowns
Using the bottom of a sturdy glass, a small plate, or a potato masher, gently press down on each broccoli floret until it flattens to about 1/2 inch thick. Work slowly so the pieces stay mostly intact. Leave any small broken bits on the pan—they will become extra crispy.
2 pounds broccoli crowns
Roast the smashed broccoli for 15–18 minutes, rotating the pan halfway through, until the edges are browned and crisping and the broccoli smells fragrant and garlicky.
Remove the pan from the oven and quickly sprinkle the broccoli with the grated parmesan and shredded mozzarella. Return to the oven and roast for an additional 5–7 minutes, until the cheese is melted, bubbly, and lightly golden in spots. Watch carefully so it doesn’t burn.
1/3 cup parmesan cheese, 1/4 cup mozzarella cheese
Remove the pan from the oven and immediately squeeze 1–2 tablespoons of lemon juice over the broccoli. Sprinkle with red pepper flakes and chopped parsley or chives, if using. Taste and adjust salt and pepper if needed. Serve hot, straight from the pan or transfer to a platter.
1 teaspoon kosher salt, 1/2 teaspoon black pepper, 1 tablespoon lemon juice, red pepper flakes, fresh parsley or chives