Finely chop the onion, carrot and celery, place them in a pan over high heat together with the wine and, when it begins to boil, cook over low heat, stirring occasionally, until the sauce becomes smooth.
Remove the pan from the heat and puree the vegetables.
Put 2/3 of the butter in another wide skillet over medium heat and when the butter melts add the rosemary, peeled garlic and beef cut into 4 slices.
Salt and pepper and when the beef has browned on all sides, add the sauce and continue to cook for 5 minutes.
Remove the beef from the pan, add the remaining butter to the pan juices and bring the sauce together over low heat, stirring until the sauce is velvety smooth.