* If you don’t have buttermilk, you can use whole or low-fat milk instead, but you’ll need to add another teaspoon of lemon juice (or vinegar) to approximate the tanginess of the buttermilk. For best results, measure ⅓ cup of milk into a measuring cup, then stir in 1 teaspoon of lemon juice (or vinegar). Let it sit for 5 to 10 minutes before adding it to the rest of the ingredients.
** I’ve listed the white-wine vinegar as an optional ingredient, but, truth be told, I always add it. However, depending on the tanginess and creaminess of your yogurt and buttermilk, you might not need it. My advice? When making this dressing for the first time, leave out the white-wine vinegar, then taste the dressing. If you want more sharpness, or you need to cut through the creaminess of the yogurt a bit more, add the white-wine vinegar. (If you want more lemon flavor or brightness, add another ½ to 1 teaspoon of lemon juice instead of, or in addition to, the vinegar.) You can also substitute white-wine vinegar for all of the lemon juice if you don’t have any lemons on hand, but keep in mind that the white-wine vinegar has a sharper taste, so you might need less. (Apple-cider vinegar could also work fine in a pinch.)
*** My boys like this dressing best with fresh chives and parsley (preferably flat-leaf Italian parsley, which is more flavorful than the curly variety), but occasionally I use only one herb or the other, depending on what’s available at the grocery store and what’s (miraculously) growing in my garden, and no one has complained. Feel free to play around with other herbs too: Dill is traditional, thyme is another good option, and basil is a particularly lovely addition in the summer. (Imagine a basil-flecked ranch dressing drizzled over a platter of perfectly ripe, thickly sliced summer tomatoes—yum!) And since you need such a small amount of fresh herbs for this dressing, I taught my kids (and my students) that you don’t even need to drag out a knife and cutting board to chop the herbs. Just use a clean pair of kitchen scissors (not the scissors you use for your arts-and-crafts projects) and carefully snip the (washed and dried) herbs into the smallest pieces you can, right into the dressing.
And if you don’t have any fresh herbs on hand, dried herbs are fine to use (although the fresh herbs really make the dressing shine). Just be sure to use less (about ⅓ to ½ the amount of fresh herbs), as the flavor of the dried herbs is more concentrated.
MAKE IT DAIRY-FREE: For the few students I taught who were sensitive to dairy, I made a dairy-free honey mustard dressing with them instead. (I’ll share this recipe soon!) I haven’t tried making this ranch dressing dairy-free, but if you want to give it a try, you could start by substituting unsweetened non-dairy yogurt and unsweetened non-dairy milk for the Greek yogurt and buttermilk, then go from there, adjusting the amounts of the other ingredients to suit your tastes.