Drain the mushrooms (or clean and chop fresh mushrooms). Heat 1 tablespoon of olive oil in a pan and sauté the shallot with the garlic until translucent, then add the mushrooms. Season with pepper and salt.
Whisk eggs with milk (if you like it creamier you can use cream) and some salt with a whisk. Then roll the toast in the egg mixture so that it is well soaked. Heat 1 tablespoon of olive oil in a non-stick pan and fry the egg toast in it until it is golden.
Place the toast on a baking sheet, place a slice of Serrano ham on each of the egg toast. Spread the mushrooms on the ham, place a slice of Gouda cheese on each toast.
Place the tray in the preheated oven (180 degrees) on the top rail until the cheese begins to run.
Tip:
You can also add herbs to the mushroom mass. E.g. finely chopped rosemary or thyme taste very good.