1 t. mustard
1 t. salt
1 T. vinegar
1 ½ c. vegetable oil
Pulse all ingredients except the oil in a food processor until smooth and combined. In a slow stream, while the processor is running, add the oil until the mixture is thick, light colored, and holds it’s shape.
These are just the basics, of course. It could easily be upgraded by using premium ingredients like a fresh chicken egg, dijon mustard, white wine vinegar, fresh lemon juice, or extra virgin olive oil. You could add chopped herbs, horseradish, or maybe a little truffle oil. Even then, I don’t think that would bring the retail price much above $2.99, do you? How would you doctor up some homemade mayonnaise?