Preheat oven to 400. Combine flour, sugar, powder and salt with a whisk. Cut in cold butter into flour mixture until it resembles fine crumbs. (this part can be done ahead and kept in refrigerator or freezer until ready to make)Stir in 1 beaten egg, chocolate chips and just enough 1/2 and 1/2 or cream until it barely comes together. Transfer on board and knead in gently loose pieces. Pat out into 1/2 in thick circle and cut equally into 12 triangles. Place 2 inches apart on a greased cookie sheet/silpat or parchment. Brush with egg wash and bake for 10-12 minutes. Place on cooling rack to cool.