In a food processor fitted with a metal blade, combine the egg, garlic, mustard, and lemon juice. Process until smooth. Season with salt and pepper. With the machine running, slowly add the oil in a steady stream, until an emulsion forms. Season with salt and pepper. Place the mayonnaise in a mixing bowl. Fold in the chopped herbs. Cover and refrigerate for 2 hours before serving. Serve the mayonnaise as a dipping sauce for fried seafood or a spread for sandwiches.
Yield: about 1 1/2 cups