In a large pan, heat up the oil with the finely chopped onion, brown it and add the mushrooms, cut into pieces, together with a few bay leaves. Season with salt and cook for around twenty minutes.
Boil and mash the potatoes and add the Taleggio cheese
cut into pieces, eggs, salt and a pinch of nutmeg. Mix well.
Pour the mushroom sauce over the base of a greased oven dish, add the potato mixture and press down lightly.
Sprinkle with breadcrumbs and bake in the oven at 180°C for 30 minutes.
You can also prepare in small, single-portion moulds.