In a small mixer bowl combine mustard; salt; paprika, if desired; and red pepper. Add egg yolks and vinegar or lemon juice. Beat with an electric mixer on medium speed till combined.

With mixer running, add the oil, 1 teaspoon at a time, till 2 tablespoons oil have been added. Add the remaining oil in a thin, steady stream. (This should take about 5 minutes.) Cover and store in the refrigerator up to 2 weeks.

Food-processor directions: In a food processor bowl combine all ingredients except oil; process till combined. With the processor running, add oil in a thin, steady stream. (When necessary, stop the processor and use a rubber scraper to scrape the sides.)