In a hot skillet, heat the butter until frothy and light yellow. Add the liver pieces, seasoning as you do so.
Fry for 45 to 60 seconds on each side. Transfer liver to a plate and set aside.
Sprinkle the skillet with sugar, add tangerine, and fry until gently caramelized on both sides.
Arrange liver, tangerine and a small pinch of sea salt on crispy toast.