The crumbly but moist biscuit yields to juicy nectarine in every bite.
Preheat oven to 400 degrees. Combine nectarines, lemon juice, and 2 teaspoons granulated sugar. Let stand 15 minutes.
Whisk together flour, baking powder, salt, and remaining 1/4 cup granulated sugar in a large bowl. Using a pastry blender, cut in butter until mixture forms small pieces. Stir in cream. Fold in nectarine mixture.
Turn out dough onto a lightly floured surface. Pat into an 8 1/2-inch round. Using a 2 1/2-inch cutter, cut out 8 rounds, and transfer to a parchment-lined baking sheet. Brush with cream; sprinkle with sanding sugar. Bake until golden brown, 20 to 25 minutes. Let cool on a wire rack.
Shortcakes can be stored in an airtight container up to 1 day.