Cut the mozzarella di bufala into cubes, making sure to keep the whey coming out of it. Weigh the collected liquid and add enough milk to obtain a total of 280 g of liquid. Blend the mozzarella with the mixture of milk and whey and a pinch of salt. Pour the mozzarella into a siphon and put the siphon upside down in the fridge for an hour. Clean the asparagus by bending them until they break, then steam them until tender but still crisp. Dip the asparagus in a container of water and ice to ensure that the cooking stops and keeps them so green and crisp. With a potato peeler cut the flaked bacon. Heat the milk on the fire without boiling it. Beat the egg yolks with grated Parmesan and freshly ground pepper. Pour the hot milk in the egg yolks and without stopping to whisk with a whisk (by hand, it is not necessary to use the electric ones) cook the sauce in a bain-marie. Remove the sauce from the fire as soon as it is veiling the spoon and begins to take consistency. Cook the conchiglioni in plenty of salted water and drain well from all the cooking water. Stuff the conchiglioni with the mozzarella foam kept in the fridge in the siphon. Brown the flakes of bacon in a non-stick pan on both sides until they become crisp. Pour a little sauce on the bottom of the plate. Lay the conchiglioni on the sauce. Decorate each conchiglione with an asparagus tip. Complete the dish distributing the bacon flakes on the sauce.