1cupneutral oil - vegetablesafflower or light olive oil (extra virgin is not recommended)
optional add-ins - See Notes***
Immersion Stick Blender: quickest and easiest method
Use the beaker that came with the stick blender or a mason jar with an opening big enough for the immersion blender to fit. Place the egg into the beaker, then the mustard, lemon juice and/or vinegar, salt, pepper, and lastly the oil. Let it settle for a few seconds to ensure the egg is at the bottom and the oil has risen to the top. Place the immersion stick on top of the egg and turn it on keeping it in place. Once everything starts to blend you can slowly start to raise the immersion stick slightly. You will see everything start to blend and come together within seconds. Keep raising and lowering until all the oil is blended and you have a beautifully creamy mayonnaise. I find using the immersion stick immediately creates a thicker mayonnaise.
Add the egg into the blender along with the mustard. Cover and blend until well combined. With the blender still running, remove the cap on the cover and very very slowing drizzle in the oil. This is very important. Trust me, I know. I have failed because of my impatience. Once it is emulsified, stop the blender and add in the salt, pepper, and lemon and/or vinegar. Blend to combine.
Place the egg and the mustard into the bowl of the food processor and pulse once or twice to combine. With the processor running, slowly, very gradually, drizzle in the oil. This should take about a minute. Once it is all added and emulsified, season with salt, lemon and/or vinegar, and pepper, if using. Process until combined. You may find making the mayo using the food processor a little thinner than if the immersion blender was used. Don't worry. It will thicken up in the refrigerator. Yes, you can use it immediately after making it just note it may be thinner but still creamy and delicious.
*To make an egg room temperature, simply place an egg in a bowl with some warm water for a few minutes. I find using a room temperature egg creates a better emulsion.**You can use any type of mustard you like. I use either yellow mustard, Dijon, or mustard powder, successfully.If your mayonnaise breaks (separates) it's because the oil was added too quickly and all the beating in the world won't make it come together. To re-emulsify, place an egg yolk into a bowl, and slowly whisk in the separated mayonnaise. Another way is to use some prepared mustard (not mustard powder) and put it in a bowl. Using a whisk, add the separated mayonnaise mixture slowly into the mustard while whisking.***Optional Add-ins: Cayenne for spice Garlic - minced or granulated for flavor Dill for a great veggie dip Tarragon alone or mixed with dill for seafood or veggie dip Ketchup for a sandwich spread Dijon as a spread for chicken, fish, or sandwiches