01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large bowl, combine broccoli florets with olive oil, minced garlic, kosher salt, black pepper, and red pepper flakes if using. Toss until evenly coated.
03 - Spread the 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 are golden brown.
05 - Remove broccoli from oven and immediately toss with lemon juice and zest. Transfer to a serving dish, garnish with parsley and Parmesan if desired, and serve warm.