Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
     1/4  cup           fresh lemon juice
     3/4  cup           vegetable oil
     1/2  cup           chopped onions
     1/2  cup           chopped green onions
     1/4  cup           chopped celery
   2      tablespoons   chopped garlic
   2      tablespoons   prepared horseradish
   3      tablespoons   Creole or whole-grain mustard
   3      tablespoons   prepared yellow mustard
   3      tablespoons   ketchup
   3      tablespoons   chopped parsley
   1      teaspoon      salt
   1      teaspoon      cayenne
     1/8  teaspoon      freshly ground black pepper

Preparation:

Put all the ingredients in a food processor and process for 30 seconds. Use immediately or store. Will keep for several days in an airtight container in the refrigerator.