Put the potatoes in a pot of boiling salted water and cook for 15 minutes. Meanwhile, blanch the asparagus in another pot of boiling salted water for 4 minutes and drain in a colander.

Preheat the oven to 190 ° C / 375 ° F / gas 5. Take a baking dish to spread the filo pastry leaves, brush with melted butter as you go, leaving about 2.5 cm hanging over the edge. Make about five layers of thickness. Place a clean, damp dishcloth on top and set aside.

When the potatoes are ready, mash with the cheeses. In another bowl, mix the eggs and cream and incorporate the potato and cheese mixture. Grate the nutmeg, season well with pepper, and mix. Spread the mixture over the filo pastry, then fold the edges of the pastry and crimp together to form a border. Take the blanched asparagus and line up across the filling, making sure to cover everything. Brush all over with melted butter and put in the preheated oven for about 20 minutes, or until golden and crispy. Let rest for 10 minutes. Serve as a quiche for a quick lunch or dinner, with a salad.