Preheat oven to 400°F. Line a large baking sheet with parchment paper.
Clean the cauliflower and trim off the green outer leaves. Pull apart the florets from the base and cut any of the larger stems into smaller pieces.
Toss the cauliflower florets and the stem pieces, along with the shallots and garlic with the olive oil.
Add half of the Parmesan, salt and red pepper flakes and toss to coat all well.
Turn the cauliflower out onto the prepared baking sheet.
Sprinkle the remaining Parmesan evenly over the top.
Roast for 10-15 minutes, or until the cauliflower is al dente, but beginning to brown on top and the cheese is getting crispy.
Remove from oven and serve hot!