In warm weather (like almost always) you should go to St Cugat to the Monestir de Sant Cugat either with the S2, the scooters, or the car to take some tapas.
Some other restaurants recommendations in St. Cugat are the Bar Tomas for tapas, la Bolera to go to a Braseria, or Teleferic in hope they sell pinchos again (stopped due to the Pandemic).
