Start by crushing the Ice in a blender. Add the Cranberry Juice (more or less to taste) and Sour Mix, blend a few more seconds. Add the Vodka and blend again. If done properly, this drink should be frothy for a bit, and then separate as it sits. Serve in cocktail or margarita glasses. It won’t hurt to put it in the freezer for a short time (enough to slush it some).