Preheat your oven to 200°C (390°F). Line a baking sheet with parchment paper or a silicone mat for easy cleanup.
Trim the broccoli into bite-sized florets, aiming for even sizes so they cook uniformly. Place the florets into a large mixing bowl.
Finely mince the garlic cloves, smashing and chopping until very small. Add the garlic to the bowl with the broccoli.
Pour the olive oil over the broccoli and garlic, then sprinkle with a pinch of salt and red pepper flakes if using. Toss everything together until all the florets are evenly coated and fragrant.
Spread the coated broccoli in a single layer on the prepared baking sheet, ensuring the florets aren’t crowded so they can crisp properly.
Place the baking sheet in the oven and roast for about 20-25 minutes. Halfway through, shake the pan or use tongs to flip the florets for even browning.
Check for doneness: the edges should be crispy and golden, and the garlic should smell fragrant and slightly toasted. If the garlic darkens too quickly, remove earlier to prevent bitterness.
Remove the broccoli from the oven and squeeze fresh lemon juice over the hot florets. Toss gently to coat and brighten the flavors.
If desired, sprinkle grated Parmesan cheese over the hot broccoli for a salty, nutty crunch. Let sit for a couple of minutes to allow flavors to meld.
Serve immediately while still warm, with crispy edges and aromatic garlic, or transfer to a platter for sharing.
