Many from scratch recipes substitute mayonnaise for the combination of egg yolk and oil. If you are uncomfortable eating raw egg, you are welcome to do the same, but the result will be much lighter in color, less concentrated in flavor, and heavier in calories. Even when using egg and olive oil, your dressing may be lighter or deeper in color depending on the mustard that you use and on the quality of your eggs. If you are inexperienced making an emulsion using a whisk or are just short of time, you can mix the ingredients using an immersion blender, but this technique can alter the flavor slightly. This dressing keeps well in the refrigerator for up to 1 week.