Blanch the liver in salted water for a few minutes Remove with a slotted spoon and let cool slightly. Chop.
Heat 2 tablespoons butter or olive oil in a large, wide pot and wilt scallions and liver together, stirring until lightly browned, 7-8 minutes. Add the tomatoes, salt and pepper and add enough water just to cover the contents of the pot. Cover and let simmer over a low heat until the liver is very tender and the juices are thick, about 1 hour. Ten minutes before removing from the heat, stir in the remaining 2 tablespoons butter or oil and dill. Remove and serve.
Bon appetit!