Preheat an oven to 180 degrees/gas 4.

Make the bechamel sauce by melting the butter in a saucepan over a medium heat and then adding the flour to form a thickish paste. Keep mixing with a wooden spoon as it turns into a stodgy sort of yellow paste.

Keep cooking it over a gentle heat for at least three to four minutes to “cook out” the flour. Keep stirring as it has a tendency to burn.

Gradually add the milk, whisking all the time to prevent lumps (or subdue them). Cook over a low heat, mixing or whisking, and it will eventually rid itself of lumps but will resemble a soft dough rather than sauce, which is what you want. So much liquid comes off the spinach later that you will be delighted with the final consistency.

Add the Dijon mustard, season well, and stir in a few pinches of freshly ground nutmeg, to taste.

Wash the spinach well and de-stalk it to remove the thickish bits that might be too stringy once cooked.

Next, in a large saucepan on a medium heat, saute the greens in the olive oil with the butter, garlic and chilli until they are wilted. Mix in the bechamel sauce, which will start to disperse and become sauce-like as you mix it. Pour the whole mixture into a gratin dish.

Sprinkle the grated cheese over the top, add more nutmeg and a few small knobs of butter, and bake for 25-35 minutes until bubbling.