Preheat oven to 350°F (175°C).

Bring a pot of water to a boil.

Add cauliflower florets to the boiling water.

Cook the cauliflower for about 10 minutes, or until slightly tender.

Drain the cauliflower thoroughly.

Place the drained cauliflower in a 2-quart casserole dish.

In a small bowl, melt margarine.

Add Parmesan cheese, bread crumbs, salt, and crushed red pepper flakes to the melted margarine.

Mix well to combine the breadcrumb mixture.

Sprinkle the breadcrumb mixture evenly over the cauliflower in the casserole dish.

Top with grated Cheddar cheese.

Bake in the preheated oven for 20 minutes, or until the cheese is melted and bubbly.