Heat butter, cut spring onions into 2 cm long pieces and steam with onions for 5 min until soft.
Blanch (scald) tomatoes, peel, remove seeds and cut into cubes, add to onions and steam for 5 min until soft.
Add whipping cream, parsley and spices and fold in shredded cheese until melted. Pour the chorreada sauce over the hot potatoes form.
Tip: Cook only with high-quality spices – they are the be-all and end-all in a good dish!