Mayonnaise

First came across this in Julia Child and I love it better (almost) than Hellmann's. It sure is helpful to have when you run short and can't run out!

Blend in electric blender on high for 30 seconds
1 whole egg, 1/4 t dry mustard, 1/2 t salt

Add 1 T lemon juice, or vinegar and blend for 10 seconds

Uncover blending jar and blending at high speed SLOWLY pour up to 1 cup of olive or salad oil in to center of mixture in a very thin stream of droplets. The sauce begins to thicken after 1/2 c. has gone in. Sometimes this is where I stop. If it blends too far it gets thin again and you'll have to make salad dressing out of it. If the blend is too thick, blend in a few more drops of lemon or vinegar.

Spoon into a wide mouthed jar and chill.