Combine the raisins, a splash of vinegar, and warm water just to cover in a bowl and plump for 20 minutes. Drain.
Bring a large pot of water to a boil and add salt until it tastes like the sea. Add the spaghetti and cook according to the package directions. Start tasting a minute or so ahead of time so you don’t overcook it. With a ladle or a measuring cup, scoop out about 1/2 cup of the cooking water, and drain the pasta well.
Meanwhile, pour a healthy glug of olive oil into a large skillet over medium-low heat. Add the garlic and pine nuts and let them toast very slowly until lightly browned, about 5 minutes. Add the chile flakes and cook for another 10 seconds so they can bloom, then add the drained raisins.
Increase the heat to medium, add the chard stems, season with a bit of salt and black pepper, and cook slowly until the stems are slightly tender, 3 to 4 minutes. Add the torn chard leaves and a splash of water (use the pasta water, if the timing works), cover the pan, and cook until the leaves are wilted, 2 to 3 minutes.
Add the drained pasta and the butter to the chard and toss well. Taste and adjust the seasoning with more salt, black pepper, or chile flakes. Grate a bit of Parmigiano over everything, drizzle with more olive oil, and pile into bowls. Serve with more grated cheese.
Excerpted from Six Seasons by Joshua McFadden (Artisan Books). Copyright © 2017. Photographs by Laura Dart and A.J. Meeker.
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