Wash fresh spinach well, then fry in a pan over high heat until reduced and watery.

Thaw frozen spinach according to packaging instructions. Then drain well to ensure that not much water remains (which would make your lasagne all watery).

Meanwhile, prepare your béchamel: melt the butter in a saucepan. Once melted, add the flour all at once, stir and add a little milk. My Mum's trick for making a good béchamel is to let the mixture thicken (stirring constantly with a whisk to avoid lumps), add a little milk, let it thicken, add a little more milk, and do this three or four times in a row until you've finished the milk and obtained the right texture.

Preheat the oven to 355°F/180°C on natural convection/static heat high and low. In an ovenproof dish, place a little béchamel sauce, some lasagna sheets to fill your dish, a little spinach and a few slices of goat cheese.

Repeat the operation on several layers until you've used up all the ingredients.

Sprinkle with grated mozzarella and bake for 15-20 minutes.