To start with, pre heat the oven at 425° F (220° C) / 400° F (200° C) fan.
Using sharp knife, cut the florets into ½ inch slices with maximum flat edges. Set it aside.
In a bowl, combine olive oil, pepper flakes, garlic, lemon zest and juice and salt and pepper.
Place the cut cauliflower florets on baking sheet in a single layer and drizzle the prepared dressing.
Bake it in the oven for 15 minutes.
You can flip the florets here. Sprinkle chopped walnuts, grated parmesan cheese, chopped parsley and top the lemon slices.
Pop it back in the oven and bake for another 10 minutes until crisp golden edges.
Serve immediately.