Thinly slice the garlic, shallots and bell pepper.
Heat a spoonful of olive oil in a pan, add the garlic, shallots and pepper and gently sauté for 5 minutes.
Cut the morcilla into cubes and add to the pan. Stir-fry for 5 minutes or so, until the morcilla sis crispy and the peppers are soft.
Add the tomatoes, cover the pan and steam for 5 minutes or so, until the tomatoes start breaking up.
Add the sherry and prawns, turn up the heat and put the lid on. After two-three minutes, take the lid off - the prawns should be pink now (If you use pre-cooked prawns, juts stir them in to warm through.)
Stir for a minute or so to reduce the sauce. Add the fresh herb and serve immediately.