Combine first 4 ingredients in a bowl; cut butter into dry ingredients with a pastry blender until crumbly. Add 3/4 cup whipping cream and next 3 ingredients, stirring with a fork until dry ingredients are moistened. Knead dough in bowl 2 or 3 times to incorporate dry ingredients.
Turn dough out onto a lightly floured surface; knead 3 or 4 times. Pat dough to 3/4" thickness; cut with a lightly floured 1 1/2" round cutter. Place scones on a lightly greased baking sheet. Chill 20 minutes. Brush scones with 1 tablespoon whipping cream, and sprinkle evenly with 2 tablespoons sugar.
Bake at 375º for 18 to 20 minutes or until scones are golden. Serve warm.