-David Lebovitz is a brilliant chef who has authored several cookbooks and lives in Paris. He blogs under his name David Lebovitz.
-If you can’t get buttermilk, mix one part milk (whole or lowfat) with one part plain yogurt (regular or lowfat) to approximate the taste. Any kind of blue cheese, domestic or imported, should work well.
-The touch of red wine vinegar gives the dressing a little extra acidity, and if you don’t mind the faint pink color, you can use that in place of the lemon juice or white wine vinegar. I like chunks of cheese in the dressing but if you want it smooth, feel free to run it through the blender or food processor.
-from me: Bleu or Blue? What's the difference? From the source of all knowledge (not Facebook, Wiki): Bleu is the traditional French word, where the "fromage bleu" was invented. Blue is English. In American stores it can be spelled either way, though many bleu cheeses are imported from Canada or France. If it's from a local dairy, you'll probably be buying blue cheese.