The bull is an enduring symbol of Spain and can be seen gracing many a souvenir, from tea towels to postcards, but bulls are also a favourite on Spanish menus: rabo de toro, or bulls tail, is a popular tapas dish. A more uncommon sight on menus, but a favourite in markets across Spain are criadillas, or bulls testicles – you might need a strong stomach to sample this delicacy.

Criadillas is found in...