Pre-heat oven to 425° F and line a large baking sheet with wax or parchment paper
Place butter cubes in food processor with 1 cup of flour, pulse until crumbly. Add remaining cup of flour and the baking powder, sugar, and salt. Pulse for another 5-10 seconds
Add wet ingredients: heavy cream, apple cider vinegar and vanilla extract. Pulse for another 10-20 seconds until the crumbles are moist.
Dust your hands with flour and gather the dough mixture into a ball and transfer to a floured surface. Knead the dough 5 or 6 times and roll the dough using a rolling pin. You will want to roll the dough out into a large circle about 12 inches in diameter and ½ inch thick.
Use a round cookie cutter (I use the top of a 3 inch wide ramekin) to cut out 8 circles.
Brush the tops with egg wash and bake in the oven for 10-12 minutes or until the tops are golden. Transfer to a cooling rack when done.