Heat oven to 425°F. Line cookie sheet with cooking parchment paper. In large bowl, stir Bisquick mix, sugar and cocoa. Cut in butter, using pastry blender (or pulling 2 table knives through ingredients in opposite directions), until mixture looks like coarse crumbs. Stir in 1 cup of the chocolate chips.
In small bowl, mix 1/3 cup whipping cream, the vanilla and egg. Add to crumb mixture, stirring with fork until soft dough forms. On cookie sheet, pat dough into 8-inch round. Cut into 10 wedges, but do not separate wedges.
Bake 15 minutes or until set. Cool 10 minutes; carefully separate wedges.
In small microwavable bowl, microwave 2 tablespoons whipping cream and remaining 1/2 cup chocolate chips uncovered on High 30 to 60 seconds or until chips can be stirred smooth. Drizzle over scones.