Combine dry ingredients in a bowl or your food processor
If using food processor, pulse until butter is small and well blended pieces or cut in butter by hand using a pastry cutter
Add in the sour cream and water and mix well
Pulse again until well mixed
Add more water if it is too dry (just a little at a time.)
Knead a few times on the counter and roll out to 1 inch thick
Use a biscuit cutter to cut or dip a drinking glass into flour and cut
Freeze individually on a cookie sheet
After they are frozen, place in a freezer bag to store
Bake frozen or thawed on an ungreased cookie sheet
Bake at 400 for 15-17 minutes or until top is golden. If frozen bake for 3-5 minutes longer.
Twice during the baking process baste the tops of the biscuits with melted butter
Notes
Use cold butter, sour cream, egg and milk. Leave it in the refrigerator until you are ready to start.
Don't overwork the dough. Use a pastry blender or dough hook to combine the dough until it looks shaggy. There will still be small pieces of butter in the dough and that is what makes a flaky biscuit. As those pieces of butter melt, they give off steam which helps create those flaky layers.
Baking powder is an important ingredient in this recipe so make sure you are using fresh baking powder, not the stuff that's been sitting on your pantry shelf for years.
Use your hands to bring the dough together. Do not use a rolling pin to roll out the dough. Use your hands to pat the dough into a one inch tall circle.
Do not twist the biscuit cutter when cutting the dough, this will seal the edges of the biscuit and prevent those flaky layers from forming.
The trick to a nice tall biscuit is to roll your dough out to about 1 inch thick.