We wash the mushrooms and dry them well or wipe them with a damp cloth. We remove (and reserve) the feet. Boil the hats in plenty of water for three minutes. We remove and let drain on a colander, placing them upside down so that they do not accumulate water.
Heat a little oil in a pan and fry the onion, previously chopped, for ten minutes. Add the mushroom feet, also chopped, and sauté for a couple of minutes. Next we water with the white wine, we turn up the heat and let it evaporate.
Add the flour and stir, letting get toasted a little before adding the cream cheese and milk. Season to taste. Mix well and cook over low heat for ten minutes. Add the Gouda cheese, cut into small cubes, and let it temper.
Finally, we turn on the oven at 180 ºC with heat up and down. We spread the farce over the mushrooms and sprinkle with a little breadcrumbs. We place on a baking tray covered with vegetable or aluminum foil, and bake for 20-25 minutes or until the surface is golden. We serve immediately.