4 tablespoons butter, 3 tablespoons minced shallots, 2 (14 1/2-ounce) cans low sodium broth, 1 cup tawny port wine, 2 cups fresh whole cranbrries, 1 tablespoon balasaic vinegar, 2 tablespoons chopped fresh rosemary, a pinch or two or three red pepper flakes, 5 tablespoons canned whole cranberry sauce, 1 tablespoon sugar, 1 large backstrap loin brought to room temp, 1 tablespoon virgin olive oil. in a 2-quart saucepan, melt 1 tablespoon of the butter over medium-high heat. add shallots; saute for a few minnutes. add beef broth, boil until reduced by half. add port wine, cranberries, vinegar, rosemary and pepper flakes. boil until reduced again by half, about 10 minutes. stir in cranberry sauce and sugar.a (sauce may be prepaired to this point 1 day ahead and reheated) whisk in 2 tablespoon butter. salt and pepper to taste. preheat oven to 350f. season backstrap with salt and a liberal grinding of pepper. heat olive oil and remaining 1 tablespoon of butter in large skillet set over medium high heat. wen very hot, but not smoking, sear backstrap on all sides( 30-40 seconds per side) remove from skilet and place on baking sheet. place in oven for about 15-25 let stand 30 minutes before carving.