Step one:
Preheat the oven to 220°C fan. Cut the cauliflower into large florets and slice the stem into 2cm pieces. Place on a baking tray with any tender leaves, drizzle with olive oil, season well, and roast for 25 mins until starting to char at the edges.

Step two:
While the cauliflower roasts, melt the butter in a saucepan over medium-high heat. Once foaming, stir in the flour and cook for 4-5 mins until golden and nutty. Lower the heat, then gradually whisk in the milk and cream, a little at a time, until you have a smooth, glossy sauce.

Step three:

Grate the Applewood and Gruyere cheeses and add three-quarters to the sauce along with the mustard and 1 tsp Nutmeg. Stir until melted and season to taste.

Step four:
Transfer the roasted cauliflower to a deep baking dish. Pour over the cheese sauce and top with the remaining grated cheese.

Step five:
Bake for 20-25 mins until golden and bubbling. Finish with finely chopped chives and serve hot.