2 1/2 cups all-purpose flour
1 cup sugar
2 1/2 teaspoons baking powder
1/2 cup butter, cut into tablespoons
1 large egg plus 1 large egg yolk
1 tablespoon whole milk
1 teaspoon vanilla extract
In a large bowl, combine flour, sugar, and baking powder. Using a pastry blender, cut in butter until mixture resembles coarse crumbs.
In a small bowl, whisk together egg, yolk, milk, and vanilla. Add egg mixture to flour mixture, stirring until liquid is almost combined. Using your hands, work dough until it just comes together into a large ball. Shape into a disk.
Cover disk with plastic wrap. Refrigerate 1 hour.