1. In a bowl or a food processor, mix flour, sugar, baking powder, and salt. Cut butter into chunks and add to flour mixture. Cut in with a pastry blender or pulse until mixture resembles coarse crumbs.
2. In a small bowl, whisk together half-and-half and egg. Reserve 2 tablespoons half-and-half mixture; add remaining to flour mixture along with chocolate, nuts, and cherries. Stir with a fork just until evenly moistened.
3. Scrape dough onto a floured surface and, with lightly floured hands, squeeze dough together into a ball. Pat dough out into a 7-inch round about 1 3/4 inches thick. Cut into eight equal wedges.
4. Place wedges 2 inches apart on a buttered or cooking parchment-lined 12- by 15-inch baking sheet. Brush tops of wedges lightly with reserved half-and-half mixture (discard any remaining).
5. Bake scones in a 350° regular or convection oven until tops are browned, about 25 minutes. Let cool about 10 minutes on baking sheet, then serve warm or let cool completely.