Preheat oven to 400 degrees. Whisk together flour, granulated sugar, baking powder, and salt in a medium bowl. Using a pastry blender, cut in the butter until thoroughly combined. Using a rubber spatula, stir in the cream.Advertisement
Turn out dough onto a lightly floured work surface. Pat dough into a rectangle about 1/2 inch thick. If dough is too soft to cut smoothly, place in freezer until firm enough. Using a 2 1/4-inch fluted cutter, cut out rounds, and transfer them to a parchment-lined baking sheet. Brush tops with egg; sprinkle with sanding sugar. Bake until edges of shortcakes begin to turn golden brown, about 20 minutes.