Heat oven to 400 degrees
Combine flour, sugar, baking powder, baking soda and salt
Shred frozen butter into dry mixture. Stir together well, until crumbly
Add dried fruit, chips and nuts, stir
Blend together the sour cream, whipping cream and egg
Make a well in the center of the dry mix. Pour egg mixture into well and using a fork, combine with the dry ingredients to form a ball.
Sprinkle flour on a cutting board. Knead the dough a few times, until no longer sticky. Press dough into an 8-inch circle. It will be about 1-1/2 inches thick.
Brush egg white over dough and sprinkle sugar
Cut dough into wedges using a pizza cutter.
Arrange wedges about 2 inches apart on cookie sheet covered with parchment paper.
Bake on mid rack 15-17 minutes