Pork Tenderloin With Cabbage

Name: Pork Tenderloin With Cabbage
Ingredients: 4 tablespoons unsalted butter; 1/2 small head red cabbage, cored and thinly sliced; 1/3 cup golden raisins; 3 tablespoons red wine vinegar, plus more to taste; 1 cup apple cider; 1/2 teaspoon ground allspice; Kosher salt and freshly ground pepper; 2 pork tenderloins (1 3/4 pounds total), halved crosswise; 1 tablespoon extra-virgin olive oil; 1 1/2 cups low-sodium chicken broth; 1 teaspoon all-purpose flour; 2 tablespoons horseradish, drained