Benihana Ginger Salad Dressing

1/2 cup minced onion
1/2 cup peanut oil
1/3 cup rice vinegar
2 tablespoons water
2 tablespoons minced fresh ginger
2 tablespoons minced celery
2 tablespoons ketchup
4 teaspoons soy sauce
2 teaspoons sugar
2 teaspoons lemon juice
1/2 teaspoon minced garlic
1/2 teaspoon salt
1/4 teaspoon black pepper

Combine all ingredients in a blender. Blend on high speed for about 30 seconds or until all of the ginger is well-pureed.