Preheat the grill.
For the potato mash: Lightly toss the potatoes with olive oil and season with salt and pepper. Place on a roasting pan and roast for 12-15 minutes. Place the roasted potatoes in a mixing bowl, add the cream and butter. Mash the potatoes till they are sort of creamy but with lumps. Season with salt and pepper.
For the tuna: Make a slit on the side of the steak about 2 inches wide. Slide the piece of fois gras into the pocket. Season the tuna with salt, pepper, essence and lightly oil the steak to prevent from sticking to the grill. Place on the grill. Grill for about 2 to 3 minutes on each side.
For the sauce: In a saute pan, heat olive oil, add the shallots and caramelize for 2 to 3 minutes. Add the red wine and reduce by half. Add in the veal stock and simmer 1 to 2 minutes. Stir in butter and season with salt and white pepper. Remove the steak from the grill.
To assemble, place a good amount of the roasted mashed potatoes in the center of the plate and place the tuna right on top. Spoon the sauce around the tuna. Garnish with essence and grilled green onions.
Yield: 1 serving