Heat a tbsp of olive oil in a large frying pan or wok. Once sizzling, add the onion and cook over a high heat until softened and well coloured.
Stir in the Demerara sugar and continue to fry for two minutes.
Pour over the red wine and boil until just half the liquid is left.
Stir in the marmalade to thicken the sauce and season with salt and freshly ground black pepper, to taste.
Heat the remaining olive oil in a separate frying pan. Fry the cured ham over a medium heat for a few minutes until the slices become very crisp. Remove and drain on kitchen paper, keeping warm to one side.
With the same pan and oil still hot, add the liver steaks and fry for two to three minutes on each side, depending on their thickness, to leave them moist and pink inside. Season with salt and freshly ground black pepper, to taste, and rest for a few minutes.
Spoon the red wine onions onto plates with the steaks and ham.
Serve with a green salad scattered with orange segments and drizzled with crème fraîche.