01 - Set oven to 425°F and line a baking sheet with parchment paper or a silicone mat.
02 - Bring a large pot of salted water to a boil. Add broccoli florets and blanch for 2 to 3 minutes until just tender yet still bright green. Drain and pat completely dry.
03 - Arrange broccoli on the prepared baking sheet. Gently flatten each floret with the bottom of a glass or potato masher.
04 - Drizzle smashed broccoli with olive oil, then sprinkle with sea salt, black pepper, garlic powder, and chili flakes if using.
05 - Distribute freshly grated Parmesan cheese evenly over the seasoned broccoli.
06 - Roast in the oven for 18 to 22 minutes until edges are crisp and cheese is golden brown.
07 - Serve immediately, garnished with extra Parmesan or a squeeze of lemon if desired.