TO DO ON CHRISTMAS EVE:

Peel and chop the potatoes into 4cm chunks. Pop them in a large saucepan of water, ensuring they're completely submerged, and cover with a lid. Leave overnight at room temperature.

TO DO ON CHRISTMAS DAY:

Preheat your oven to 220°C/200°C fan/gas mark 7.

Pour enough oil into a deep baking tray to cover the bottom and pop into the oven.

Pop the large saucepan of potatoes (keeping the water) on high heat with 1 tsp salt and bring to the boil. 

Boil the potatoes for 7-8 mins or until the edges are soft.

When ready, drain in a colander and sprinkle over some of the flour (2p: 20g, 3p: 30g, 4p: 40g).

Shake to fluff up the potatoes, then carefully add them to the hot baking tray, turning in the oil.

Season with salt, sprinkle over the dried rosemary, then roast on the top shelf until golden, 45-50 mins. Turn halfway through.

Serve in a large bowl.

TO DO ON CHRISTMAS EVE:

Cut the cauliflower into florets (like small trees), halving any large ones.

Pop the cauliflower onto a baking tray. Drizzle with oil, season with salt and pepper, then toss to coat. Spread them out in a single layer.

Roast on the middle shelf until golden brown and tender, 18-20 mins. Turn halfway through.

Meanwhile, grate the cheese.

While the cauliflower roasts, melt the butter in a large saucepan on medium-high heat.

Once hot, stir in the oil (see pantry for amount) and some of the flour (2p: 20g, 3p: 30g, 4p: 35g). Cook until it forms a paste, 1-2 mins - you've made a roux! 

Stir in the water for the sauce (see pantry for amount) a little at a time, followed by the vegetable stock paste.

Bring to the boil, then stir continuously and simmer until thickened, 1-2 mins.

Mix the creme fraiche into the sauce, then remove from the heat.

Once roasted, stir the cauliflower and three quarters of the cheese into your creamy sauce until well combined and all the cheese has melted.

Add a splash of water if it's a little too thick. Taste and season with salt and pepper if needed.

Transfer the cauliflower cheese to an appropriately sized ovenproof dish. Sprinkle over the remaining cheese. Set aside to cool. Once cooled, cover and pop your cauliflower cheese into the fridge ready to be reheated tomorrow.

TO DO ON CHRISTMAS DAY:

Place the cauliflower cheese onto a baking tray and add to the middle shelf of your oven until golden and bubbling, 15-20 mins.

Serve in the dish.