Heat oven to 375°F. Blend flour, baking powder, baking soda and sugar. Cut in butter with pastry cutter. Stir in buttermilk until mixture just holds together. Add fresh or lightly floured blueberries and lemon zest and stir until blended. Place mixture on a floured surface and roll ¾ inch and cut into 2 inch rounds. Place on a prepared baking sheet. Brush tops with cream. Bake 15 minutes or until golden brown. Yields approximately 50 scones.