Preheat your oven to 200°C (180°C fan). While it heats, wash and dry your cauliflower, then cut it into bite-sized florets. Try to keep them roughly the same size so they cook evenly. You should hear a clean snap when you break them apart – that is a sign of fresh cauliflower.

Toss the cauliflower in the baking dish. Add the olive oil, salt, pepper, and smoked paprika directly to the dish. Use your hands or a spatula to coat every floret. The paprika should turn the cauliflower a deep, rusty orange. Spread them out in a single layer and roast for 15 minutes. The edges will begin to brown and caramelise, and you will smell a nutty, sweet aroma.

While the cauliflower roasts, make the cheese sauce. In a saucepan over medium heat, melt a knob of butter (about 20g) and whisk in the plain flour. Cook for one minute, stirring constantly – the mixture will bubble and smell slightly toasty. Slowly pour in the double cream and stock, whisking all the time to avoid lumps. The sauce will thicken to the consistency of single cream after about 3 minutes.

Remove the saucepan from the heat. Stir in the Dijon mustard, then add the grated cheddar and Parmesan a handful at a time. Keep stirring until the cheese has completely melted and the sauce is smooth and glossy. Taste it – it should be rich, savoury, and slightly tangy from the mustard. Season with a pinch more salt if needed.

Pour the cheese sauce over the roasted cauliflower. By now, the cauliflower should be tender when pierced with a fork and lightly charred in spots. Gently stir everything together so every piece is coated. The dish will look very saucy at this stage, but that is exactly what you want – the cauliflower will absorb some of it as it bakes.

Sprinkle the breadcrumbs and extra cheddar over the top. For the crunchiest topping, toss the breadcrumbs with a teaspoon of olive oil first. Spread them evenly over the bake. The dish should look like a golden, speckled landscape before it goes into the oven.

Bake for 15 minutes, uncovered. When it comes out, the top should be bubbling at the edges and deep golden brown. The breadcrumbs will have formed a crisp crust that crackles when you tap it with a spoon. Let it rest for 5 minutes – the sauce will settle and thicken slightly, making it easier to serve. Garnish with fresh parsley if you like.