All is said with the name of this tapas bar: Las Bravas in reference to the best patatas bravas of Madrid. The patatas bravas is a fried potato, served with a special sauce. So special here that it is supposedly patented. One will appreciate also squids or tortillas.
In short it is really not expensive, not dietetic at all but.. Terribly good!! Several addresses because Las Bravas is a chain of tapas restaurants in Madrid.