This is a proper grown-up breakfast for a cold day. The toast itself would be substantial enough but once topped with the dark bosky mushrooms and the deep mineral taste of the just-cooked livers it takes on a whole new level of fortification.
This dish can be a bit of a frying pan juggle so you may need to keep things warm in a low oven as you go. The most important point is to serve it as soon as the livers are cooked and they are still blush in the middle.