Yield: varies on size of egg yolk to oil ratio, but about 3/4 cup.
Tools: a whisk (I use a silicone covered one which I love for this), and a stainless steel bowl
Ingredients: (should all be room temperature for the best emulsification results)
1 egg yolk
1 tsp. dijon mustard
1-2 tsp. white wine vinegar (and/or lemon juice)
pinch salt, pinch white pepper
175-200ml good quality vegetable-based oil, include 10-15ml olive oil in total amount if desired
(A medium-sized yolk has the capacity to emulsify about 180ml of oil, hence the variance above)
Optional: herbs, spices, sun-dried tomatoes, lime zest, etc.
1. Whisk egg yolk in a bowl, with dijon, vinegar, salt, pepper and a bit of lemon juice, if using, until well blended and frothy. If using powdered spice (curry, mustard powder), also add them now.
2. Place your bowl on a non-slip surface (a moist towel), or better yet, use the cook's trick: place your bowl in the rim of a slightly smaller saucepan or pot, with a kitchen towel in between. You want to have both hands free to be able to simultaneously whisk and pour the oil without having to stop to grab onto your whizzing bowl.
3. Pour the oil in a thin stream (almost a dribble) while constantly whisking; keep doing so until your mixture starts to thicken and take on that mayo consistency. Once your ingredients are well-emulsified, you may start to pour the oil a little faster until the desired consistency is achieved.
4. Add finely chopped fresh ingredients as desired (basil leaves and sun-dried tomatoes, capers and olives, etc.) and season to taste (add lemon juice, pepper, salt).
Notes on the oil:
Be sure to use the best possible oil as it makes a huge difference in the taste; peanut oil tastes the most neutral, but is more expensive than canola or sunflower, although there's not a huge difference in price if you buy organic/first-press types. Mayo made with 100% olive oil is too strong for my taste, so I generally just use a bit to enhance the overall flavour.