In a large bowl, cream butter, sugar and salt. Add eggs and peppermint extract; mix well.

Remove 1 cup of butter mixture and place in a medium bowl; set aside. To remaining mixture, add red or green food coloring (until desired shade) and 1/4 cup crushed candy canes. Add 2 cups flour and 1 tsp. baking powder; mix well. On a large sheet of waxed paper, press dough into a large rectangle (about 1/2-inch thick), cover with a second sheet of waxed paper and chill 30 min.

Add melted chocolate to reserved butter mixture; mix well. Add 2 cups flour and 1 tsp. baking powder and mix until well blended. On a large sheet of waxed paper, press dough into a large rectangle, (about 1/2-inch thick) cover with a second sheet of waxed paper and chill 30 min. Remove dough rectangles from refrigerator and roll each into larger (9x16-inch) rectangles. Brush one layer with egg white and place other layer on top. Trim long edges. Roll up lengthwise into a tight roll, resulting in a 16-inch long log. Wrap in plastic wrap and chill 30 min.

Preheat oven to 350ºF. Slice into 1/2-inch slices, and bake on parchment-lined cookie sheets for 10 to 12 min. Cool completely.

Break up chocolate and melt in a shallow, microwave-safe bowl for 30 sec. Stir and continue to microwave in 10-sec. increments, stirring until smooth, but not warm. Dip half of each cookie into melted chocolate and sprinkle with crushed candy canes. Place on waxed paper until chocolate sets.

Store at room temperature in an airtight container for up to one week.