In a large pot, bring water to a boil.

Cut your cauliflower head into florets. Rinse them and put them in the boiling water.

Cook for 15 minutes until tender but not fully cooked.

Then, drain the water and set it aside.

Pre-heat the oven at 400F.

In a small pot, on medium-low, melt the butter and add the flour; stir well using a wooden spoon. This is a roux.

Turn down your heat to low and gradually add the milk. Stir constantly for 4-5 minutes or until the sauce is velvety. This is your bechamel.

Pour the cheddar cheese and stir until fully combined and melted; your Mornay sauce is ready.

Assembling: in a baking dish (11" x 7"), put the florets and pour the cheesy mixture all over. Generously top with parmesan cheese and sprinkle with thyme.

Bake in the oven for 30 minutes or until the top is perfectly golden.

Serve and enjoy!