Place a large saucepan over a high heat and add the butter.

Once the butter has melted and become a light golden brown, add the garlic and fry for 30 seconds. Then, add the chestnut and portobello mushrooms along with a pinch of salt and generous grind of black pepper.

Sauté the mushrooms over a high heat for 10 minutes, stirring often until they start to soften and release their juices. Continue to cook the mushrooms until all the juices have evaporated and the mushrooms and an even golden brown all over.

Place the spinach in a large mixing bowl and cover with cling film. Microwave for 3 minutes until darkened and wilted, before squeezing the spinach out over the sink to remove as much moisture as possible.

Stir the walnuts through the mushroom mix and cook for a further minute.

Dust over and stir through the flour and cook for 2 minutes.

Pour the white wine into the pan, stir well, and allow the wine to reduce by ½.

Add the milk and cream and bring to the boil, stirring constantly. Reduce the heat to medium and stir through the nutmeg, cheese, parsley, mustard, and wilted spinach.

Zest over the lemon and squeeze in its juice. Taste and adjust the seasoning and remove the pan from the heat.

Preheat the oven to 200℃.

In a 25 x 28cm baking dish, interlayer the filling and blanched pasta until they are both used up. Spread the ricotta over the top layer of pasta and then scatter over the grated cheese.

Bake in the preheated oven for 30 minutes until bubbling and golden on top.