Ingredients

• 1 tablespoon grated white onion (or yellow)
• 1/2 cup creole mustard (or other spicy mustard)
• 2 tablespoons ketchup
• 1 teaspoon Worcestershire sauce
• 2 teaspoons prepared horseradish
• 1 teaspoon finely chopped garlic
• 1 teaspoon fresh lemon juice
• 1 1/2 teaspoons paprika
• 1/4 teaspoon white pepper (if you don't have white, use black)
• 1/8 teaspoon finely ground black pepper
• 1/8 teaspoon cayenne pepper (to taste)
• salt, to taste
• 1/2 cup olive oil
• 1/4 cup finely chopped heart celery
• 2 teaspoons finely chopped parsley