Preheat oven to 400°F/200°C, line a large baking sheet with parchment paper and set aside.
If your frozen broccoli is in a steerable bag then steam in the microwave as suggested by the instructions on the bag.
If not, place frozen broccoli florets on a microwave safe bowl with 2 tablespoons of water, cover then microwave on high for 3-4 minutes until fork tender. Drain well and let them cool down for a minute or two until you are able to handle. Pat dry.
Depending on the size of each floret, pour ¼ to ½ teaspoon oil on the parchment paper, smear a bit them place one floret over.
Using the bottom of a glass cup smash the floret so it is flattened. Top with some parmesan cheese and sprinkle some pepper flakes on top if using.
Repeat this with the rest of the florets until done.
Bake in the center of the oven until the cheese is crispy for about 20 minutes.
Serve with your favorite dipping sauce.