Place all ingredients in a food processor. Pulse until you achieve a desired consistency. Be careful not to over pulse or you end up with a kind of nut butter. You only need a few short pulses to achieve a texture similar to coarse sand.
Store in a sealed container. Will stay fresher longer if kept in the refrigerator or freezer.
Notes
For a tree nut free version you can substitute the walnuts for pepitas or more sunflower seeds. This recipe works well with other nuts too.