In a large mixing bowl, combine first four ingredients.
Beat with an electric mixer until light and fluffy, scraping the bowl occasionally.
Combine flour, baking powder and salt in a small mixing bowl; add to the creamed mixture.
Refrigerate at least 1 hour.
In food processor, grind cranberries. (I used the shredding blade).
In a small bowl, combine ground cranberries, walnuts and orange peel; set aside.
On a lightly floured surface, roll dough into a 10-inch square.
Combine brown sugar and milk; spread over dough.
Sprinkle with the cranberry mixture, leaving about a ½-inch edge at both ends of dough; roll up tightly, jelly-roll style.
Wrap with waxed paper; chill several hours or overnight.
Remove waxed paper and cut roll into ¼-inch slices and place on well-greased cookie sheets.
Bake at 375° for 14-15 minutes or until edges are light brown.
Do not over-bake!
Rotate cookie sheets on oven racks half way through baking time.
Cool completely.