01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large bowl, toss broccoli florets with olive oil, minced garlic, kosher salt, black pepper, and crushed red pepper flakes if using, until evenly coated.
03 - Spread broccoli in a single layer on the prepared baking sheet.
04 - Roast for 18 to 20 minutes, stirring halfway through, until broccoli is crisp-tender and edges turn golden brown.
05 - Remove from oven and immediately toss with lemon juice and zest.
06 - Transfer to a serving platter. Garnish with parsley and Parmesan if desired. Serve warm.