DIRECTIONS
Blend butter with Worcestershire, rosemary, garlic, salt and pepper to create a paste. Rub evenly over entire roast. Let stand at room temperature for 1 hour. (Make-ahead - Roast can be refrigerated overnight, uncovered; remove from fridge 1 1/2 hours before roasting.)
Arrange a single layer of carrots in large cast iron skillet or small roasting pan to create a vegetable “rack.” Pour 3/4 to 1 cup broth into the skillet (just enough to moisten all the carrots but not submerge), place roast on top of carrots.
Roast in preheated 450°F oven for 20 minutes. Reduce heat to 325°F and roast for 1 1/2 hours or until internal temperature registers 145°F. Remove roast to cutting board, rest, tented with foil, for 20 minutes before slicing across the grain. Meanwhile, use tongs to remove carrots to serving bowl, keep warm.
Place skillet over burners. In small bowl, whisk remaining broth with cornstarch, stir into roasting juices, whisking to scrape up browned bits. Simmer, stirring, until thickened. Strain into gravy boat and serve with sliced roast.