Heat the oil in a frying pan, add the morcilla or black pudding and cook for 1–2 minutes until crisp all over. Remove from the pan and set aside.
Add the spring onions, garlic and fennel seeds to the pan and cook for 30 seconds. Stir in the broad beans and stock, season and cook for 3–5 minutes until the beans are just cooked through.
Return the morcilla or black pudding to the pan, add the mint and heat through. Scatter with extra mint and serve with crusty bread.