Place the egg yolks in the container of a blender or food processor. Add a little of the lemon juice and then process until combined. With the motor running, gradually add the olive oil, a few drops at a time, until a thick emulsion begins to form. Then add the remaining oil in a very thin, slow stream until all the oil is incorporated and the mixture is thick. Add lemon juice to taste and season with salt and pepper. If the mayonnaise is too thick, thin with a little water. Of course, you may also make this in a bowl with a whisk. The resulting texture will be a little lighter.