Steps

• Clean the asparagus. Wash them gently, cut them to more or less the same length, and cook them in the asparagus steamer leaving the tips out for 15-20 minutes. I let them steam in the vegetable steamer with a little water inside the casserole below for 10-12 minutes. Boil the potatoes: wash the potatoes to remove any dirt residues. Place them, with the skin on, in a pot with unsalted cold water. Bring to a boil and cook for about 25-30 minutes: it’s not easy to estimate the exact cooking time due to the different consistency or size of the potatoes. To check the cooking, just stick them with a fork (or the tip of a knife): if they slide off, they are cooked. Remove them from the water, peel them, transfer them to a bowl, and mash them. Season with salt, the beaten egg, and the oil. Mix all ingredients well. Grease a baking dish and sprinkle with breadcrumbs. Arrange a first layer of potatoes, add the asparagus by lining them up neatly, and complete with asiago or mozzarella. Cover with the remaining potatoes, add a few knobs of butter and bake in the oven at 356°F for 25 minutes.