Make a smooth pasta dough from the ingredients. Form into a ball, wrap in foil and rest the dough for 1 hour.
Cut the meat and bacon into strips and pass them through a fine mincer. Crush juniper berries, peppercorns and bay leaf spice in a mortar, put in a Reindl form with sherry and red wine. Bring to a boil, reduce to 2 centiliters, cool, strain through a fine sieve. Add to the meat with the egg white, double cream and game glace, season with salt, season with pepper and prepare everything together into a smooth farce.
Roll out the pasta dough thinly and make rectangles of five by ten centimeters with the pastry wheel. Place a spoonful of filling on each and fold the rectangles together to form Maultaschen.
For the sauce, peel onions and garlic clove and chop very finely. Clean the mushrooms and dice 80 grams, set the rest aside. Melt 10 grams of butter, sauté half of the onions and garlic until translucent. Briefly sweat the finely chopped mushrooms. Pour whipping cream, boil to half. Season with salt and pepper, strain through a sieve. Reduce game stock to half, season. Cook the Maultaschen in boiling salted water for 5 to 6 minutes. Cut remaining mushrooms into slices. Melt remaining butter, sauté remaining onions in it. Fry the mushrooms on both sides for one to two minutes, season with salt and pepper.
Arrange the Maultaschen on plates.