Ingredients
- 1½ teaspoons kosher salt, plus more for seasoning
- 1½ cups (4 ounces) dried bow tie pasta
- ½ cup dried kasha (buckwheat groats)
- ½ cup olive oil, plus more as needed
- 1¼ pounds mixed mushrooms, cleaned, stemmed, and quartered
- 1 tablespoon Dijon mustard
- ¼ cup distilled white vinegar
- 1 teaspoon sugar
- ¼ teaspoon coarsely ground black pepper
- ½ medium red onion, sliced
- 4 small radishes, thinly sliced (½ cup)
- One 5-ounce package (5 cups loosely packed) baby arugula leaves

