Prepare 600g cauliflower (one head) by removing the stalk and cutting off the florets. Cut any large florets in half so that they are all a similar size

Bring a large pan of water to the boil and add 1 tsp table salt before adding the prepared cauliflower

Cook the cauliflower for 5-6 minutes until you can just insert a knife into the stem. You don't want the florets to be fully cooked at this point

Drain the cauliflower and allow to steam dry thoroughly

Mix together 100g extra mature cheddar cheese, 35g Parmesan and 35g mozzarella and set aside

Preheat your oven to 180°C (fan assisted, 200°C non fan assisted)

In the pan you cooked the cauliflower in, melt 30g butter over a medium/low heat

Once melted add 3 tbsp plain flour and stir until a paste forms. Cook for 2 minutes

Gradually add 400ml of semi skimmed milk. Start by adding just a splash and stir until it is completely absorbed and only then add another splash. Don't be tempted to add a lot at a time

Once you have added all of the milk, add in 3/4 of the cheese

Stir until all of the cheese is melted and then add ½ tsp mustard powder, ¼ tsp white pepper and 1 tsp sea salt. Stir well

Add the cauliflower to the cheese sauce and carefully stir making sure all of the cauliflower is coated in the sauce

Pour the cauliflower into an oven proof dish. I used one that was approximately 20x20cm

Scatter over the reserved cheese

Cook for 20-25 minutes or until the cheese on top is your desired shade of brown