Heat oven to 400 degrees. Spray a cookie sheet with baking spray.
In a large bowl whisk together baking mix and 1/3 cup sugar. Cut in cold butter with a pastry blender or fork until crumbly (bits of butter are good!)
In a small bowl whisk together egg, yogurt, 1/4 cup whipping cream and lemon peel. Add to the baking mix mixture until just combined. GENTLY, fold in blueberries without breaking them if at all possible (they look better this way!)
Place dough on the prepared cookie sheet and shape into an 8 inch circle. Brush dough with 1 tablespoon whipping cream, then sprinkle with 1 tablespoon sugar. Dip a sharp knife into additional baking mix (or flour) and cut circle into 8 wedges, but do not separate.
Bake until golden brown, approximately 15-20 minutes. Recut wedges along the lines you made before baking and gently move to a rack to cool for 5 minutes.
In a small bowl combine powdered sugar, lemon juice and additional lemon peel, if using. Drizzle over the scones and serve warm.