1 oz (30 g) butter
2 tablespoons extra-virgin olive oil
1 lb (440 g) filet mignon
salt and pepper
2 tablespoons balsamic vinegar>
Put butter and olive oil in a hot skillet on medium heat. As soon as butter starts foaming add fillets.
Brown the fillets on all sides.
Add salt and pepper.
Cook for about 5 minutes. Add balsamic vinegar. Let the balsamic vinegar evaporate, and serve at once.