I've mentioned previously that I drink two teaspoons of Walnut oil each morning, and try to eat about 8 nuts every evening. Their medicinal qualities are renowned.
Otherwise we make a good Walnut Pesto simply by substituting Walnuts for Pine Nuts, Lady Magnon uses quite a lot for her various cakes, and a lot go into our Summer salads. That's about it.
Of course, any that are left-over from the previous year make wonderful fire-lighters!