In large skillet, cook 2/3 cup chopped onion gently in 3 or 4 tablespoons butter until tender and lightly browned. Add 1/2 pound fresh mushrooms, coarsely chopped and cook about 5 minutes. Add 1 teaspoon salt and 1/4 teaspoon pepper. If possible, buy veal cut as for scaloppine, but in 8 pieces, each 5 x 6 x 1/4 inch. Spread with mushroom mixture; roll and fasten with string and poultry pins. Brown meat on all sides in a little more butter, using same skillet as before. Add 1/2 cup dry white wine and 1/2 cup water; cover; simmer until tender, 30 to 35 minutes. Add a little more water as needed.

Remove birds when done; sprinkle into liquid in pan 2 tablespoons flour. Pass sauce in pan through blender. Return to pan with enough water to make 1 1/2 cups. Add birds, heat. Best served with rice and a green salad.