Mayonnaise is a process of forcing egg yolks to absorb a fatty substance, oil in this case, and to hold it in to a thick and creamy suspension. But as the egg yolks do not have to be warmed, the sauce is that much simpler to make. You can make it by hand, blender or food processor. I've used the food processor as it produces a larger and better sauce.
Since homemade mayonnaise is uncooked, be sure to use the freshest eggs possible, and ones that you are reasonably sure are free from salmonella. Homemade mayonnaise will last three to four days in the refrigerator.
One should also exercise caution when serving homemade mayonnaise to young children, the elderly and those with compromised immune systems.
Mayonnaise is used as the base for other sauces, such as tartar sauce and thousand-island salad dressing. Aioli is garlic-flavored mayonnaise. Another classic emulsion sauce is hollandaise, which is a cooked mixture of butter, egg yolks and lemon juice.
To make 2 cups of mayonnaise in the food processor, fitted with the steel blades, you'll need:
1 egg and 2 egg yolks (at room temperature)
1/4 teas. dry mustard
1/2 teas. coarse salt
Freshly squeezed lemon juice and/or white wine vinegar
2 cups of the best quality olive oil and/or vegetable oil
Additional salt, pepper, lemon juice or wine vinegar as needed
Process the egg and yolks for 1 minute.
With the machine still running, start adding the oil in a stream of droplets, continuing until you have used half the oil and the sauce is very thick. This is a VERY important step. Add the oil too quickly and your sauce will break, and you'll have to trash the whole thing! I believe most food processors have in the top of the food pusher, a small "pin-hole" like mine does (I believe is a standard on Cuisinart processors). This is what that pin-hole is for, adding oil or other liquids in a very thin, slow stream.
Thin out with lemon juice or vinegar, then continue with the oil. Season carefully with more salt, pepper, lemon juice and/or vinegar.
The mayonnaise should be chilled and used within 3-4 days. As mentioned above, you can use this mayonnaise as a base for other sauces and dressings