In Barcelona, expect to find a mix of traditional Spanish dishes along with Mediterranean-infused Catalonian classics. While here, make sure to sample Spanish staples including jamón ibérico, manchego cheese, tortilla española (potato omelet), gazpacho (cold soup), and patatas bravas (sautéed potatoes typically served with a spicy aioli). And considering the city borders the Mediterranean Sea, you should indulge in paella accordingly. But when in Catalonia, try the Catalan versions of paella. There's arròs a la catalana, which features much of the same ingredients of paella except the dish doesn't use saffron, a key ingredient in Spanish paella. Fideuà is another paella-like dish with a Catalan spin, only instead of rice you get noodles.
Catalonian cuisine is big on meat and fish. And while that may not sound too far off from the rustic, meat-heavy fare found throughout the rest of Spain, the difference here is that the Catalans like to mix both of them together in one dish. Mar i muntanya is the name of the phenomenon, so don't be alarmed if while in a restaurant, you notice a dish coming out with chicken and shrimp together on a plate. If that sounds too heavy for your liking, there are plenty of lighter options that are quintessentially Catalan. Grilled vegetables are surprisingly big for a place that loves pork. (Sausage is another staple here. Instead of focusing on chorizo, go for the regional botifarras sausage). One of the most traditional Catalan dishes available is escalivada, which is grilled eggplant and red peppers mixed with olive oil and garlic (sometimes with anchovies) served on top of bread. There's also the vegetarian-friendly, and favored pa amb tomàquet snack, or bread spread with a mix of olive oil, garlic and crushed tomatoes. And if you're visiting from December to early May, seek out a calçot cookout. Calçots are a type of spring onions native to the province, and it's a Catalan pastime to char them on a grill and dip them in romesco sauce. Also part of the pastime? Wearing bibs (often emblazoned with calçots) and eating outside, where the grilled calçots are spread among newspaper. (If that sounds familiar, it's the same way crab and lobster is consumed in the USA.)
Whatever you decide to eat while in Barcelona, make sure to leave room for dessert. Crema catalana is the Catalan version of creme brulee. Cheese is also dessert here. Mel i mató is a goat cheese drizzled with warm honey and accompanied by walnuts. Cava, or Catalan sparkling wine, goes great with these too.