Chocolate Nut shortbread cookies

I love to use hazelnuts in these, but you can substitute walnuts or pecans instead.
Ingredients - Makes 4 dozen shortbread cookies.
2 and 1/2 cups all purpose flour
3/4 cup cocoa
1 teaspoon baking powder
1/2 teaspoon cinnamon
1 teaspoon coarse sea salt or Kosher salt ( plus extra for sprinkles)
1 and 1/2 cups butter, softened, not melted
1 and 1/2 cups sugar
2 eggs (if small, use 2)
1 teaspoon vanilla extract
1 cup toasted and chopped walnuts, pecans, or hazelnuts
Steps
  1. Whisk flour, salt, cocoa, cinnamon, and baking powder in a large mixing bowl.   Set aside.
  2. In the bowl or your stand mixer or in another mixing bowl, beat softened butter and sugar until fluffy.  ​
  3. Add eggs, one at a time, beating a tiny bit after each addition.  Pour in the vanilla and beat until combined.
  4. Carefully stir in the flour mixture, then beat on low speed until just mixed through - not too much.
  5.  Toast the nuts on a cookie sheet in the oven or in a skillet on low heat.  Don't burn or brown them - toast just a bit.  Stir into cookie dough.
  6. Remove dough from bowl and roll out into two logs about 2 inches in diameter.  Wrap the rolls separately in plastic wrap and refrigerate for 3 hours or overnight, if desired.
  7. Cover a cookie sheet with baking parchment or grease it with butter. 
  8. Remove plastic wrap from dough logs and cut into round slices about 1/2-inch thick.  Place slices on the cookie sheet about 1-inch apart and sprinkle with just a bit of Kosher or coarse sea salt.
  9. Bake in preheated 325° F oven until just done - about 12 minutes or so. (Press lightly in the center to see if it springs back a bit).  Don't bake too long - with chocolate cookies, it's hard to tell when they're done.