Heat a dash of extra virgin olive oil in a thick-bottomed frying pan.
Lightly flour the pork slices on both sides, just to pat them dry.
Brown the pork slices for a minute in the hot frying pan, then turn them and let them brown on the other side. Add a tablespoon of mustard, half a teaspoon of mustard seeds and then pour the beer over the meat, stirring with a wooden spoon to dissolve the mustard into the beer.
Season with salt to taste and cook for 4 up to 5 minutes until the beer is almost completely evaporated, leaving its aromas and a velvety sauce.
Serve the meat with a side dish of boiled potatoes, left whole and seasoned with a knob of salted butter.