Preheat the oven to 450 degrees. In a small bowl, whisk together 1/2 cup half-and-half and the egg.
In a large bowl, combine the flour, sugar, baking powder and salt. Blend in the butter with your fingertips until the mixture resembles coarse crumbs. Add the oats and apple and toss. Stir in the liquid mixture until the dough just forms a ball.
Turn the dough out onto a floured work surface. Pat into a 7-inch round; cut into 8 wedges. Transfer to a parchment-paper-lined baking sheet and brush the tops with the remaining 1 tablespoon half-and-half. Bake until golden, about 20 minutes. Transfer to a rack to cool.