Use a spoon to combine the lemon juice, oil and cream (I use anything leftover – soured, single, double, Elmlea, whatever), then add the sugar and season. You have to TASTE this to get the proportions of everything just to your liking, then you finely chop the onion (or chive, or fresh parsley) and add to the dressing. I use this dressing to coat crisp iceberg lettuce on its own or even just finely sliced cucumber. Adding parmesan makes it more like a Caesar.