Season the sirloin with salt and pepper and cook it in a frying pan to the desired doneness. Let stand for 5 min.
In the meantime, make the sauce in a sauté pan: fry the butter, the shallot and the chopped garlic until it is poached.
Deglaze the pan where the sirloin was cooked with the fino, add the juices to the sauté pan with the shallot and butter, let the alcohol evaporate, add the mustard and cream. Bring to a boil and add the goat log, mix and boil until it has the desired consistency. Add salt and pepper.
Cut the sirloin into thick cubes and serve with the zucchini and french fries, add sauce without covering the meat and serve with more sauce on the side.