3/4 Cups of oil (I used olive. Walnut oil leads to a more buttery flavor, hazelnut oil to a nutty flavor, and truffle oil to a nice earthy taste but... $$)
1/8 teaspoon salt
1 Tablespoon lemon juice, you can get this from half a lemon
1/2 teaspoon Dijon mustard (You may also use ground mustard seed. The woman I asked at Central Market says Dijon mustard in recipes refers to the liquid form, but I'm used to using ground mustard seed when I make mayonnaise.)
You will either use a hand mixer (electric beater) or a blender. If using a hand mixer, start by pulling out a medium glass bowl. Boil water in a pot and place the bowl over the boiling water. Just making the bowl a little warm makes a big difference. Mayonnaise is an emulsion and the formation of an emulsion is much easier when the molecules are moving quickly (a.k.a. heat).
[To get the egg yolk: crack an egg in the middle over a bowl and hold the egg vertically. Remove the top half of the shell and transfer the egg yolk from one shell to the other until all of the white has dropped into the bowl.] Set up your hand mixer or blender. Place the egg yolk and salt in the blender or bowl. Add the mustard and lemon juice, and blend on pulse. Keep the blender running as you add oil very slowly. This will take a few minutes. Don’t rush the process. When all the oil has been added, you have mayonnaise (not the "mayo" Hellmann's sells, this is real mayonnaise)! The mayonnaise may be refrigerated for up to five days.
Mayonnaise is also a fun word to spell..