Method
1. Warm your oven to 200°C/Fan 180°C/Gas 6. Pop a large pan of salted water on the hob, cover with a lid and bring to the boil.
2. Meanwhile, trim the base off the cauliflower and slice off the leaves. Discard any woody leaves but keep the thinner, more tender ones. Slice the cauliflower into bite-sized pieces. When the water in the pan is boiling, add the cauliflower chunks and leaves. Simmer for 6-8 mins, till the florets are just tender. Drain well and set aside.
3. While the cauliflower cooks, peel and finely chop the onions. Peel and thinly slice the garlic cloves. Unwrap the Brighton blue and mozzarella cheese, and roughly chop them. Scoop the cheese into a spare bowl for later.
4. Pour 1 tbsp oil (or use 1 tbsp butter, if you prefer) into a separate large pan over a medium heat. Slide the onion and garlic into the pan and add a good pinch of salt and pepper. Fry the onion for 8 mins, stirring occasionally, till softened. When the onion is glossy, add the cornflour and cook, stirring frequently, for a further 2 mins.
5. Slowly pour the milk into the onions, stirring frequently as you pour. The milk will combine with the cornflour to create a sauce thick enough the coat the back of a spoon. Add the mustard to the sauce and stir well. Bring the sauce slowly to a gentle simmer, then stir in the chopped Perl Las and mozzarella till melted. Remove from the heat.
6. Fold the cooked cauliflower into the cheese sauce till well coated then scoop the cauliflower and cheese sauce into an overproof dish. Slide the cauliflower cheese into the hot oven. Bake for 30 mins till golden brown and bubbling. Rest in the dish fior a few mins, then serve with potato wedges and a peppery green salad.
7. Get Ahead
You can assemble the cauliflower cheese the night before you want to serve it. Simmer the cauliflower and combine with the cheese sauce. Transfer it into the baking dish, then cool and store in the fridge, ready to bake in the oven for 30-40 mins till browned.
8. Love Your Leftovers
The cauliflower cheese will keep well in the fridge for up to 3 days, stored in an airtight tub. The cauliflower cheese is best reheated in the microwave till piping hot.