Roast the broccoli in the preheated oven for 10–12 minutes, just until it turns bright green and starts to soften. You don’t want it fully tender yet, just par-cooked so it can be smashed without falling apart.
Remove the tray from the oven and let it cool for 1–2 minutes so it’s easier to handle. Using the bottom of a sturdy drinking glass, a flat measuring cup, or a small plate, gently press down on each floret to flatten it into a rough disk. It’s okay if some edges crack a bit—that’s where the best crispy bits happen.
Sprinkle the grated parmesan evenly over the smashed broccoli, making sure each piece gets a generous coating. Let some cheese fall around the edges onto the foil; those little puddles bake into delicious, crispy cheese frills.
Return the tray to the oven and roast for another 10–14 minutes, or until the cheese is melted, deeply golden brown, and crisp around the edges and the broccoli is tender with browned spots.
For extra crispiness, you can switch the oven to broil for the last 1–2 minutes, watching very closely so the cheese does not burn. Pull the tray as soon as the tops are evenly browned and sizzling.
Let the smashed broccoli rest on the tray for 3–5 minutes to firm up slightly, then use a thin spatula to gently lift each piece off the foil. Transfer to a foil-lined serving tray if you like that casual, party-style presentation, and serve hot.
