I found that this dressing tasted even better the next day. And I did like it better with a bit of mayonnaise but you can certainly leave it out.
1 shallot, finely chopped
1/3 clove grated garlic
1 tablespoon lemon juice
1/3 teaspoon lemon zest
1 tablespoon white wine or champagne vinegar
2 tablespoons olive oil
4-6 tablespoons of crumbled Roquefort cheese
2 tablespoons buttermilk (preferably full fat)
1 teaspoon dijon mustard OR Colman's mustard powder
1 tablespoon mayonnaise (optional)
big pinch salt
pepper to taste
handful of parsley, roughly chopped.
crispy bacon (optional topping)
Place chopped shallot, lemon juice, zest, and vinegar in a bowl. Let it sit for a few minutes. Slowly whisk in olive oil. Whisk in cheese, buttermilk, mustard, mayonnaise (if using), salt, and pepper. Taste and adjust to your liking. I needed to add more lemon and more salt. Set aside for a few minutes and then taste again. It's amazing how the flavors shift as they integrate. You could also make it easy and throw it all in the blender. I don't use the blender for this because I like having the chunks of cheese and shallots.
Serve over wedges of iceberg or heart of romaine. Serve with extra dressing in a pitcher.