Cook pasta: Bring a large pot of salted water to boil. Cook pasta until al dente, according to package directions. Reserve 1 cup of pasta water, then drain noodles.
10 oz linguine
Mix olives and capers: Meanwhile, to a food processor, add the olives, capers and brine, lemon juice and zest. Pulse until a rough paste forms, scraping down the sides as needed.
⅓ cup pitted green olives, 2 tablespoons capers + [adjustable]1[/adjustable] teaspoon brine, 1 lemon, zested and juiced
Cook sauce: Heat olive oil in a large skillet over medium heat. Cook onion, until very soft and golden brown on the edges, about 10 minutes. Add garlic and red pepper flakes. Cook until fragrant, 1 to 2 minutes. Stir in the Swiss chard and cook until it begins to wilt, about 2 minutes.
1 large yellow onion, diced, 5 cloves garlic, minced, ¼ teaspoon red pepper flakes, 1 bunch Swiss chard, chopped, ⅓ cup extra virgin olive oil
Combine: Add pasta, salt, the olive and caper mixture, butter, and ½ cup of the reserved pasta water. Toss to coat noodles. Sprinkle with grated cheese, toss to mix. Slowly drizzle in as much of the remaining ½ cup of the reserved pasta water needed so the noodles are evenly coated with sauce. Taste and season with pepper (and more salt if needed). Sprinkle with parsley. Garnish with more cheese, if using.
1 tablespoon butter, ½ teaspoon fine sea salt, ½ cup grated Parmesan, ¼ cup chopped flat-leaf parsley, Black pepper