Place an oven rack on the center shelf and preheat the oven to 425 degrees. Line a baking sheet with foil or parchment.
Combine the broccoli florets and garlic on the baking sheet. Drizzle with the olive oil and toss to coat, then season with salt and pepper. Spread the broccoli and garlic evenly, leaving space in between for even roasting. Roast for 20 to 25 minutes, using a spatula to turn the pieces over midway through. The broccoli is ready when browned and crispy on the edges and fork tender.
Squeeze the lemon juice over the broccoli, being mindful to avoid seeds. If using, top with the cheese and/or nuts. Serve hot.
Notes
You can save the leftover broccoli stalk for a later use, such as broccoli soup.
To avoid burning the garlic, I recommend slightly thicker slices (cutting each clove into thirds or quarters lengthwise).