1. Preheat oven to 400°.
2. Combine 1/2 cup currants and 2 tablespoons water in a microwave-safe bowl. Microwave at HIGH for 45 seconds, stirring every 15 seconds. Cool 10 minutes (do not drain).
3. Combine baking mix, 1/4 cup sugar, and cinnamon in a large bowl. Cut in butter with 2 knives until mixture resembles coarse meal. Add currants, 2/3 cup half-and-half, chips, and egg white; stir until just moist. Drop dough by 1/4 cupfuls onto a foil-lined baking sheet; place pan in freezer 5 minutes. Combine egg yolk and 1 tablespoon half-and-half; brush over tops and sprinkle with 1 tablespoon sugar. Bake at 400° for 12 minutes or until golden. Cool on a rack.
4. Combine powdered sugar and 1 1/2 teaspoons water; drizzle over scones.