Preheat oven to 350 degrees
Line a baking sheet with parchment paper
Whisk together flour, baking powder, salt, and sugar into a large bowl.
2½ cups all-purpose flour, 2½ tsp baking powder, ½ tsp salt, ¼ cup granulated sugar
Grate frozen butter into mixture using a large cheese grater. Stir until distributed.
¼ cup unsalted butter, frozen
Whisk together cream, 1 egg, and vanilla in a medium bowl. Add to flour mixture, stirring until evenly moist. If the mixture is dry, add cream in tablespoon increments until a dough forms.
1 cup+ cold heavy whipping cream, 2 large eggs, ½ tsp vanilla extract
Knead dough on floured surface gently and roll out until it is roughly ¾-inch thick. Use a 2½ inch biscuit cutter to cut scones and place on prepared baking sheet.
Combine 1 tbsp cream and remaining 1 egg, whisking well. Brush tops of scones with egg wash.
Bake approximately 20 minutes.