Acidified Austrian Potato Salad

I love potato salad (of all types), but I have a problem:  mine always ends up half way to mashed potatoes by the time I'm done.  I guess there's a magic moment when the potatoes are tender but will still hold their shapes, but I never find it.  In an effort to avoid crunchy potatoes, I always overcook them.

However, I learned from Cook's Illustrated that potatoes respond to acid the same way beans do.  That is, acidic conditions keep the cell walls of beans from breaking down and becoming tender, and (slightly) basic conditions promote faster "cooking".  But potatoes cook a lot faster than beans, so instead we can use a little bit of acid -- about 2 T per quart -- to protect them from overcooking.  Conveniently, they seem to cook to the perfect tender-firm texture for potato salad, and then just hold there for another 5 minutes or so!

This particular recipe is similar to a German or Austrian style potato salad, but the same technique would work for a vinaigrette- or mayonnaise-based salad.  Still, this one is well worth a try -- it's got great flavors, and it's actually pretty healthy.

In a 12-inch skillet, bring to the boil

1. 2 pounds Yukon Gold or other potatoes, peeled and cubed
2. 1 c chicken broth
3. 1 c water
4. 1 t salt
5. 1 T sugar
6. 1 T vinegar (scant)

Reduce heat;  cover and simmer until tender, about 15 minutes.  Uncover and increase heat for 2 minutes to reduce liquid to about 1/2 cup.  (If you have more or less, you'll have to drain the potatoes, measure the liquid, and then discard some or supplement with water.  If it looks like about 1/2 cup though, just dump it all in!)  Mash together

1. 1/2 c potato cooking liquid
2. 1 T vinegar
3. 1 T Dijon mustard
4. 1/4 c vegetable oil
5. 1/2 c cooked potatoes

Fold in

1. remaining potatoes
2. 3/4 c finely chopped red onion (1 small)
3. 2 T minced cornichons or kosher dill pickles
4. 2 T minced fresh chives
5. salt and pepper to taste

Serve warm or chilled.