You don't find it in many places these days, but pestorejo (a fleshy cut of pork from the nape of the pig's neck) is an old Mérida favourite. The taste is all pork, the texture a little fatty, so it's best tried in small doses. Just as well, then, that you get a tapa of pestorejo free here when you order a drink.
There's another outlet down the southern end of Plaza de España.