Preheat oven to 375 F degrees. Line a baking sheet with parchment paper.

In a large bowl add the all purpose flour and cake flour. To it add the baking powder, sugar and salt. Mix it all together. Using a pastry blender or a fork, cut in the butter in the flour until it resembles small peas.

Add the blueberries and the chocolate chips to the flour mixture and toss them around.

In another small bowl mix the buttermilk with the two eggs and vanilla extract.

Pour the buttermilk mixture over the flour mixture and slightly mix with a fork. Turn the dough over onto a floured surface and gently knead until all the ingredients are well incorporated.

Cut the dough in half and roll each half into a 8 inch disc that's about 1 inch in thickness. Cut the disc into 8 triangles, like a pizza. Repeat with other half.

Place the scones onto the prepared baking sheet. Brush the triangles with the egg wash and sprinkle with additional sugar if desired.

Bake for 20 to 25 minutes or until the scones are golden brown.