In a medium sized bowl place the egg yolks and the mustard, together with a Tablespoon of cold water. Beat this with a hand mixer until it is well blended. While continuing to beat the mixture bit by bit add the salad oil. If the mayonnaise becomes too thick, add a little more water. Still beating the mixture add the lemon juice and then taste to see if seasoned properly. If not add more salt & pepper to taste. Store the mayonnaise in the refrigerator in a covered bowl.