Preheat your oven to 220°C (430°F). Line a baking sheet with parchment paper or a silicone mat for easy cleanup.
Trim the broccoli into small, uniform florets to ensure even roasting. Rinse and pat dry to remove excess moisture.
Slightly smash the garlic cloves with the side of a knife to help release their aroma and make them easier to roast evenly.
In a mixing bowl, toss the broccoli with olive oil, ensuring all pieces are coated evenly. Add the smashed garlic, salt, and red pepper flakes, then toss again to distribute the seasonings.
Spread the seasoned broccoli in a single layer on the prepared baking sheet, making sure not to overcrowd the pan for optimal caramelization.
Place the baking sheet in the oven and roast for 20-25 minutes, flipping halfway through, until the edges are crispy and golden, and the garlic is fragrant and slightly charred.
Check the garlic: it should be soft, fragrant, and have some charred bits for depth of flavor. The broccoli should be tender with crispy edges.
Remove from the oven, then squeeze fresh lemon juice over the hot broccoli to brighten the flavors and add a zesty contrast to the smoky garlic.
Gently toss the broccoli to coat everything evenly, then sprinkle with grated Parmesan or nutritional yeast if desired for extra richness.
Serve immediately while hot, enjoying the crispy edges, smoky garlic, and bright citrus notes. Enjoy the rich, tender vegetables with a satisfying crunch.