Preheat the oven to 350 degrees F.
Cut the puff pastry into 60 even squares. Using a pastry brush, brush each square with the beaten egg. Place the squares on a greased sheet pan. Apply the black sesame seeds to the egg wash on top of the squares in different patterns to make them look like dice. Bake the puffs until golden brown about 12 minutes. Let the puffs cool. Cut the puffs in half horizontally for sandwiching.
Clean and cut all the mushrooms. Heat a large saute pan. Add the cooking oil and saute mushrooms in small batches seasoning with garlic, shallots, salt and pepper. Spread sauteed mushrooms out onto a large tray and allow to cool. Chop the mushrooms and return them to the saute pan. Add the white wine and reduce until the liquid is almost completely evaporated. Add the cream and reduce again until thick.
Place one scoop of mushroom mixture on the bottom layer of the puff pastry and then top with the other layer to form the sandwich.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.