Imagine if someone described their favorite movie to you like this: There's, like, this nerdy farm kid who enjoys shooting animals on the weekend, and he unwittingly gets involved in some major political conflicts that he barely understands, makes out with his sister, and then uses a combination of magic and a poorly designed HVAC system to commit genocide against thousands of construction workers, technicians, and support staff, most of whom probably have families. (Oh, and spoiler alert, Darth Vader is really his father.)
And now, imagine that it's your job to go make that movie. You may well end up with a great movie of your own, but chances are, it's not gonna be too much like the original Star Wars.
That's what it's like when you're tasked with coming up with a recipe for a dish you've never tasted, from a country you've visited only once, when you were a young teenager. The Austrian-style potato salad recipe I developed for Cook's Illustrated in 2008 (warning: paywall) was certainly delicious, I can tell you that, and I'd done enough research on how Austrians make their erdäpfelsalat* to know that I'd gotten the basics right—sliced yellow potatoes, onions, and a splash of chicken broth—but it was still an interpretation based on hearsay.
*I love the literal translation of this word: "earth-apple salad."
That was then, and this is now. I recently got back home from a long trip around Europe that included dragging my wife and infant daughter all across Austria, eating all the schnitzel, wurst, and erdäpfelsalat I could find, with the idea that I'd use this "research" to help develop recipes for Wursthall, a restaurant I'm opening up later this year near my home in San Mateo. Really nailing the potato salad was one of the first things on my agenda.
We're all familiar with American and German potato salads, but less so with their Austrian counterpart, a lighter, brighter version of the dish that's simultaneously more refreshing (there's no mayonnaise in it, and relatively little fat overall) and deeper in flavor, thanks to the incorporation of chicken broth and the savoriness it brings. It's flavored with onions, vinegar, and mustard (sometimes with a bit of chopped gherkin) and bound together in a light sauce that gains its creaminess solely from the natural starch found in the potatoes.
The first hurdle I had to tackle was the potatoes. There are three major commercial varieties: starchy russets; waxy, creamy reds; and Yukon Golds, which bridge the gap in between. The potatoes I tasted in Austria were unvaryingly of the yellow variety, but they tasted fundamentally different from the ones I get back home. While ours tend to have an earthy starchiness to them, the potatoes in Austria were sweeter and creamier.
I tried adding just a touch of sugar to the water in which I boiled them, in the hopes of adding some sweetness, but the flavor ended up cloying and one-dimensional compared to the more complex natural sugars found in the Austrian potatoes.
Many recipes call for cooking mid-sized potatoes in boiling water until they're completely tender; this leaves their skins easy to rub off under cool running water. I compared this method side by side with potatoes that I peeled before cooking, as well as potatoes that I peeled and sliced before cooking. There was no question that cooking them with the skins on produced potatoes with more flavor than cooking them peeled. But cooking potatoes whole produced a different problem:
Even when I started them in cold water, it was hard to get them to cook evenly. By the time the very centers were tender, the exteriors were overly soft, disintegrating into the salad. A bit of soft potato thickens up the dressing and gives the salad creaminess, but too much turns it into cold, chunky mashed potatoes.
So how to get the nice, evenly cooked texture of sliced potatoes, but the flavor of potatoes cooked with their skins on? Easy. Just add those skins to the cooking water as the potatoes simmer.
I placed my sliced potatoes in a pot, covered them with salted water—it's essential to salt the water when boiling potatoes if you want them to come out flavorful—placed a fine-mesh strainer on top, and set the potato skins in the strainer, with the idea that their flavor would infuse the water like a tea.
It worked out great. You wind up with perfectly cooked potato slices that have all the flavor of potatoes boiled whole.
As I found out when working on the classic American potato salad recipe for my first book,** the other key for building great flavor into the potatoes is to sprinkle them with vinegar (I used white wine vinegar) while they're still hot.
** If you are reading this any time before late 2018-ish, my second book is probably not yet out.
The easiest way to do this is to drain them, then spread them out on a rimmed baking sheet.
As hot potatoes sit, they continue to release trapped moisture in the form of steam. As that water escapes, it leaves behind gaps in the potato's structure that get filled with whatever happens to be around. In things like French fries or hash, for instance, oil will move into those spaces. In this case, the vinegar ends up getting absorbed. This only happens if you add the vinegar while the potatoes are still busy losing moisture through steam.
For the dressing, I went with a pretty classic mix: a dollop of mustard for sharpness, a touch of sugar, some olive oil, some minced red onion (you can also use Vidalias or other sweet onions), a sprinkling of chives (parsley would also be tasty), some more vinegar, and some chicken broth. (In this case, store-bought low-sodium broth works just fine.)
I folded everything together, working some of the starch from the potatoes into the dressing. The salad should be far looser than a typical American potato salad. Think of it more like sliced potatoes in a vinaigrette, as opposed to a scoopable mixture. As I quickly learned, it thickens up a little as it sits and more starch gets absorbed into the dressing, so when you first construct it, it should seem almost soupy.
But hang on a minute. I still hadn't addressed the issue of the sweetness in those Austrian potatoes. Sometimes finding the solution to problems like this requires hard work and critical thinking. In this case, all it required was a bit of laziness and some post facto research. While testing, I'd bought a big ol' 25-pound bag of potatoes to work with, many pounds of which ended up accidentally left in the bottom drawer of my fridge for several weeks before I finally rediscovered them.
Imagine my surprise when, after boiling them, I found that they were noticeably sweeter and creamier in texture than the exact same potatoes pre-storage!
It shouldn't have surprised me too much. Some years back, when I was doing research for my French fry recipe, I'd learned that one of the banes of the French fry industry is an effect known as cold-induced sweetening (CIS). This is the accumulation of reducing sugars in potatoes as they sit at fridge temperatures, and it's caused by enzymatic breakdown of starch molecules. It's a bad thing in French fries or roast potatoes, which can come out unpalatably dark, but in the case of this potato salad, it was exactly what I needed to give those potatoes the right level of natural sweetness.
What I'm saying is that if you want the ideal Austrian-style potato salad, you're gonna have to do a bit of advance planning and let your potatoes just sit in the fridge for a couple weeks before cooking them.
Is that step 100% necessary? Heck no. The salad will still be delicious all on its own.
But let me ask you another question: Do you want to watch Star Wars later, or do you want to watch another good movie, with similar themes and plot points, that's almost but not quite the same, right now?
Let that answer be your guide.