Pearl onions add some sweetness to the tart cranberries, forming a lovely condiment for the pork.
8 ounces (2 cups) peeled pearl onions (see note)
1½ teaspoon kosher salt
2 tablespoon olive oil
2 trimmed pork tenderloins, about 1 pound each
Freshly ground black pepper
8 ounces (2 cups) fresh or frozen cranberries
1 tablespoon chopped fresh rosemary
½ cup red wine
Vincotto, saba, or aged balsamic vinegar, for serving
1. Heat oven to 425 degrees. Combine onions, ½ teaspoon salt, and 1 tablespoon oil in a small roasting pan and roast until onions begin to brown slightly, tossing a couple of times, about 15 minutes.
2. Coat pork with remaining oil and season with pepper and remaining salt. Heat a large skillet over high. Add pork and brown well on all sides, about 8 minutes. Transfer to roasting pan with onions; add cranberries and sprinkle with rosemary.
3. Add wine to skillet, scraping to loosen brown bits on the bottom; reduce by half, about 2 minutes. Pour into roasting pan; return to oven. Roast until meat reaches an internal temperature of 145 degrees, about 10 minutes longer. Let meat rest 5 minutes before slicing. To serve, spoon sauce, cranberries, and onions over top and drizzle with a little vincotto, saba, or aged balsamic vinegar.
Note: To peel pearl onions, plunge them into boiling water for about 30 seconds and drain. When cool, peel off the skins.