Yield: 4 servings.
1 pound button mushrooms
¼ cup olive oil
¼ cup red wine vinegar
2 tablespoons diced red onion 2 cloves garlic, whole
2 teaspoons brown sugar, packed
½ teaspoon dried oregano
½ teaspoon caraway seeds
½ teaspoon whole black peppercorns
¼ teaspoon crushed red pepper flakes (optional)
Kosher salt and freshly ground black pepper
2 tablespoons chopped fresh basil leaves (optional)
Clean mushrooms with a damp paper towel. In a large pot of boiling salted water, cook mushrooms until just tender, about 3 to 4 minutes; drain well.
In a large bowl, whisk together olive oil, vinegar, red onion, garlic, sugar, oregano, caraway seeds, peppercorns, and red pepper flakes; season with salt and pepper to taste. Add mushrooms and toss well.
Transfer to an airtight container and place in the refrigerator for at least 8 hours and up to 5 days. Turn container over every 2 hours, or once a day, depending on how long they marinate.
Serve at room temperature, garnished with fresh basil, if desired.