Prepare the lamb`s lettuce, wash it very well and drain or spin. Dice the mushrooms very small, cut the bacon into fine strips.
Heat 2 tablespoons of olive oil in a pan. Fry the bacon briefly, add the onions, garlic and mushrooms and cook with them. Deglaze with the sherry and let it boil down for a short time. Remove the pan from the stove and let it cool down.
Then whisk the mustard, vinegar and oil well, season with salt and pepper and add to the bacon and mushroom mixture. Mix everything very well.
Mix the lamb`s lettuce with the dressing in a large bowl.