Place walnuts alone in your food processor and process until the walnuts become small and crumbly. Add the (drained) dates and process again until the mixture sticks together and the dates are well processed. Add the remaining ingredients and process again until the mixture is incorporated.
Dump the mixture into a small tart pan, pressing up on the sides to build walls to hold in the filling. Set aside while you make the filling.
Place all ingredients in a high-speed blender and blend. Blend, scraping down the sides if necessary, to get a velvety consistency. This is one of those recipes that really makes use of the power of a high-speed blender.