You can also do this by hand with a pastry blender. Add the egg yolk and milk and mix well till mixture is smooth and pulls away from sides of bowl. Spread one third of the filling mixture over the rectangle, leaving about 1 on all sides free of filling. Roll as for a jelly roll, starting from a wide side. You will have a long, narrow roll.
Place rolls on a lightly greased cookie sheet and tuck under the open ends of each pastry roll.
Repeat with other two pieces of dough. Brush tops lightly with melted margarine. Bake in the center of the oven, at 350 degrees for about 30 minutes or until lightly browned. Cool 5 minutes, cut through scored lines into slices. Combine dry ingredients.