Ever since I found out how easy it is to make mayonnaise from scratch, I've been whipping together one-cup batches. I follow the basic process described by The Healthy Foodie and use my own ingredients, which includes (in addition to the egg and oil):
¼ teaspoon dry ground mustard
½ teaspoon sea salt
2 teaspoons apple cider vinegar
1 teaspoon maple syrup (optional, for a taste more like "Bell Menz")
Why go through all this fuss? Why not just eat store-bought mayo? Commercial mayo is made from inferior, highly-refined, GMO oil. Even the products sold in health food stores are made from canola oil, whose ratio of Omega 3 to Omega 6 is not favorable. Besides, homemade mayonnaise is so much more delicious, and you can vary the recipe to make a dressing. For example, you might add horseradish to complement roast beef, or Worcester sauce for a spicy sushi dish.
A batch lasts at least two weeks, but you'll probably finish it before then.
2016-12-30 SPG Edited to add the optional maple syrup.