Preheat oven to 425 degrees F. In a medium bowl, combine flour, sugar, baking powder, and salt. Add butter and cut in with a pastry blender until crumbs form.
Stir in any special ingredients. Options include nutmeg, candied ginger, raisins and cinnamon, dried cranberries, dried blueberries, or a handful of chocolate chips. Options are endless, but use dry ingredients rather than anything that would add additional moisture.
In a small bowl, whisk together egg and half-and-half. Add to flour mixture and stir with a fork until ingredients are moistened and hold together.
Knead dough by hand and gather into a ball. Transfer to a lightly floured surface; knead several more times. Pat dough into an 8-inch round. With a sharp knife, cut into 8 to 10 equal wedges.
Place wedges slightly apart on an ungreased baking sheet (or clay baking sheet). Bake until golden brown, about 12 minutes.