Preheat the oven to 425°F. Lightly grease (or line with parchment) a baking sheet.
1) In a medium-sized mixing bowl, sift together the dry ingredients, then add the butter, rubbing it in till the mixture resembles coarse meal.
2) Stir in the cranberries.
3) In a separate bowl, whisk together the half and half, orange juice, egg, and orange peel or oil. Add this mixture to the flour mixture and stir till the dough just comes together.
4) Transfer the dough to a thoroughly floured work surface, knead it a couple of times, and shape it into a 1/2"-thick round, about 8" across.
5) Transfer the round to the prepared baking sheet. Brush with milk, and sprinkle with coarse white sugar, if desired.
6) Cut the round in 10 wedges. Separate the wedges slightly.
7) Bake the scones for about 15 minutes, or until they're golden brown. Remove them from the oven, and serve immediately.