A modified recipe from the vegetarian cookbook The New Laurel's Kitchen. There's room to vary the recipe to make it suit your tastes including of course Mexican-inspired. The original recipe called for soy beans, but I don't care too much for them so I've substituted pintos-usually; sometimes black beans or red beans. I think the two magic ingredients are the celery and the vinegar. Use for burritos, as a sandwich spread, in portabella mushroom burgers, bagel topping, chip dip, etc.