sautee onion in butter until slightly brown. combine mashed potatoes, cooked onion, black pepper, eggs (not yolk) and salt.
pop open tube, there are 8 crescent rolls in a tube, seperate into 4 squares. 2 crescents per square. roll lightly to erase seams. place about 1/2 cup filling in the middle of each square. pinch together edges and place, seam down, on cookie sheet. brush top with egg yolk