1Heat oven to 400°F. Line cookie sheet with foil.
2In large bowl, stir together Bisquick mix, 1/4 cup of the sugar and the cinnamon. Cut in butter, using pastry blender (or pulling 2 table knives through ingredients in opposite directions), until mixture looks like coarse meal. Add 2/3 cup half-and-half, the chocolate chips and egg white; stir just until dry ingredients are moistened. Drop dough by 1/4 cupfuls onto cookie sheet; place in freezer 5 minutes.
3In small bowl, beat egg yolk and 1 tablespoon half-and-half; brush over tops of scones. Sprinkle with remaining 1 tablespoon sugar.
4Bake 12 minutes or until golden. Immediately remove from cookie sheet to cooling rack. Serve warm.