Clean the livers, put them to stew in 1 tablespoon butter and a little water and then remove them from the pan. Peel the potatoes, slice them and boil until semi-cooked, then drain.
Using another tablespoon of butter, in the same skillet, stew the coarsely chopped onion, add the potatoes and then the chopped tomato.
Add the livers, season them with spices and transfer everything to a baking tray. Add a cup of hot water and bake until the liquid evaporates.
Just before removing the livers with potatoes from the oven, pour the beaten cream over them and remove from the oven after 2 minutes.