Blend dry ingredients in a bowl and add the cut butter. Blend until crumbly with a pastry cutter
Freeze the entire bowl for about ten minutes
Remove the bowl from the freezer and add the heavy cream and sour cream. Mix with a fork or scraper about 8 times
Add the chocolate chips and the blackberries and fold again until blended
Put parchment paper over the bowl and gently tip the contents into the parchment paper. Gently knead about five times until a little more mixed and either cut or shape the mixture into scones. I use a scone pan that makes great scone wedges.
Glaze with heavy cream and bake for 20 minutes or until a toothpick comes out clean
Let these cool completely before removing from pan. These need to set a bit