The best Russian Dressing

I discovered how to make the best Russian dressing completely by accident one day when I was trying to save time and decided to use my microplane grater on the onion instead of chopping it finely, which is what I normally do.  And the way that the microplane-grated onion infuses the entire dressing is just really magical if you have a fresh, sweet onion.  The recipe calls for a tablespoon of the grated onion but it takes a pretty good amount of onion to get that much so make sure you have at least quarter or half of an onion to work with.  

Russian Dressing
adapted from How to Cook Everything by Mark Bittman

1 cup mayonnaise 
1/2 cup ketchup 
2 Tbs red or white wine vinegar
1/4 tsp dry mustard (or a little prepared mustard if you don't have dry)  
salt and freshly ground pepper to taste  
1 tablespoon onion (that has been grated using a microplane)

Wisk together all ingredients except the grated onion. Add 1/2 tablespoon of the onion and taste.  If you have a strong tasting onion, that may be all you want to add.  But if you have a nice fresh, sweet onion, you can add the full tablespoon. Wisk until smooth.  If it's too thick, you can thin it with some ketchup or vinegar.  

To make this into thousand island dressing, add pickle relish to taste. 

Mark Bittman recommends using this as a sandwich topping (mmmm... Reubens!) but I really like it as a dip for cut up raw vegetables.  I also eat it all the time on green salads, especially when we have Romaine Lettuce and I'd prefer a creamy dressing.

This lasts for a couple of weeks in the fridge if you don't eat it all first!