Sometimes the difference between a merely average salad and a great one is making just one component extraordinary. Take this kale salad as an example, in which I've paired the sturdy greens with toasted walnuts, blue cheese, and dried fruit, a classic combo that's guaranteed to be...pretty good. But instead of using store-bought dried fruit, like apricots or raisins, I grabbed some fresh red seedless grapes and put them in a low oven. What I ended up with were incredibly plump and juicy "raisins," which retained some of their freshness even as the grapes shriveled and concentrated in sweetness and flavor.
It takes slightly more effort and a few extra hours (mostly unattended), but the result is a salad that reaches much greater heights, each bite a surprise and a pleasure.
I tried a couple of different methods of oven-drying the grapes based on tips I found online. One claimed that blanching the grapes first would create tiny fissures in the skins that would speed dehydration in the oven later. I found that this didn't make much of a difference. Another said that cutting the grapes in half, exposing their interiors, would accelerate the process. That made sense to me in theory, but a real-world test revealed that whole grapes didn't take much longer than the halved ones to become nicely shriveled—the difference was small enough that I don't think the hassle of cutting them in half is warranted.
That's all good news, since it means your best bet is also the easiest: Pop the whole grapes into a low oven—either 200°F (93°C) if the convection setting is on, or 225°F (107°C) if not—and, in about three hours, they should be nicely dehydrated, while still retaining a trace of their former juicy bite. It's an extremely hands-off process, and burning the grapes isn't much of a risk at such low temperatures, so, despite the time involved, there's not much effort or attention needed.
Assembling the rest of the salad is easy-peasy. The most important thing to know is that kale improves greatly if you rub the leaves with oil first. As Kenji has written before, it's the oil in a vinaigrette that softens and tenderizes hardy green leaves like kale, not the vinegar. By pre-applying a light coating of oil, we can get a jump start on softening those kale leaves and reducing their toughness.
For the blue cheese, you have a lot of options. In this salad, I prefer one that's sweet-salty, with a slight creaminess. A French Bleu d'Auvergne is a good choice, as is Cashel Blue or Maytag Blue. Personally, I'd avoid a very crumbly, spicy blue, since I think it'd be a little too intense with the kale, and I'd also steer clear of overly soft and sweet blues, like Gorgonzola Dolce (otherwise one of my favorites—just not for this purpose).
The real interest in this salad lies in the interplay between the plump dehydrated grapes, the nutty roasted walnuts, and the funky cheese, all held aloft in the arms of those kale leaves. That means keeping the dressing simple and classic, using our basic recipe made with olive oil, white wine vinegar, shallot, garlic, and mustard. It does everything it needs to, adding moisture and enough tartness to brighten things up—especially important here, given the rich creaminess of the cheese and intense sweetness of the grapes—but not competing with the salad's star ingredients.
There's only room for so much extraordinary in one salad bowl, after all.