Mix together chicken mince, 1/4 cup (65ml) water, grated onion, eggs and salt and pepper. Mix in enough bread crumbs to make a soft, mouldable mixture.
Heat oil in a large frypan and brown chicken mixture over medium heat.
Roll out the puff pastry. Place mixture along the long edge of the pastry. Roll up and tuck ends under. Place on an ungreased baking tray.
Bake at 220 degrees C for 12 to 15 minutes, or until golden.
Meanwhile, prepare the mushroom sauce. Melt butter or margarine in a small pot. Stir in flour. Add soy sauce, onion soup mix, 1 cup (250ml) water and white wine; stir until thick. Stir in mushrooms. Pour over meat roll when serving.