Demerara Sugar Shortbread

1 cup unsalted butter, softened
1/2 cup packed Demerara-style sugar
1 tbsp. granulated sugar
1/2 tsp. salt
2 cups all-purpose flour, sifted
1/4 tsp. baking powder
1 cup chopped walnuts

In bowl and using wooden spoon, cream together butter, Demerara sugar, granulated sugar and salt until light and fluffy. In separate bowl, whisk flour with baking powder; stir into butter mixture until just combined. Stir in walnuts.

Press into parchment paper-lined 9 inch round metal cake pan. Score to make 16 to 20 wedges. Using fork, prick once or twice per wedge.

Bake in 325 degree oven until lightly browned and tester comes out clean, 45 to 50 minutes. Let cool in pan on rack for 10 minutes. Using sharp knife, cut through score lines (leaving in pan). Let cool completely.