For the sauce:

Heat the olive oil in a large skillet over medium-low heat. Add the shallots and garlic to the pan and sweat them for 1 minute. Throw in the thyme, marjoram, bay leaf, cloves, and juniper berry and sweat for 1 minute. Add the red wine and let the mixture simmer until the wine is mostly cooked off and the sauce starts to thicken slightly, about 20 to 25 minutes. Stir in 1/2 cup of the demi glace, cook for 1 minute, then taste. If the sauce needs a little more richness, add more demi glace until it tastes evenly rich and smooth. Stir in the butter until it is just melted. Taste the sauce again and season with salt, and pepper, if necessary.

For the steak and turf:

Preheat the oven to 400 degrees F. Preheat a grill or cast iron pan over high heat.

Remove the steak from the refrigerator 30 minutes before cooking so the meat is at room temperature. This helps the meat to cook evenly. Coat the steak in 2 tablespoons olive oil. Season the steak with salt, and pepper. Sear the steak on both sides, about 2 minutes per side, until browned. Transfer the steak to the oven for 10 to 12 minutes. Remove from the oven and let rest before slicing. While the steak is in the oven, season the fish well with salt and pepper. Wrap thin slices of potato around each piece of fish, overlapping slightly. Do this with each slice overlapping the last by 1/4-inch until the fish is wrapped. Heat a nonstick pan over medium heat and add 1 tablespoon olive oil. Season the potato-wrapped fish with salt and pepper and add the fish to the pan with the potato overlap facing down. This will help seal the potatoes on the fish. Cook each side until the potato is crispy and fish is cooked through. Transfer the cooked fish to a paper towel. Keep warm.

For the mushrooms:

Melt 1 tablespoon butter in a large skillet over medium heat. Add the corn to the pan and cook until lightly browned. Remove the corn from the pan to a bowl. Add another 1 tablespoon of butter and then stir in the shallots. Cook the shallots until softened, about 5 minutes. Remove the shallots to the bowl with the corn. Add in the remaining 2 tablespoons butter and raise the heat to medium-high. Add the mushrooms and cook until they start to brown, but are still firm. Add the sherry vinegar and stir. Simmer until reduced down and almost cooked out. Add the corn and shallots back into the pan. Stir to combine. Season the mushrooms with salt and pepper. Keep warm.

For the leeks:

In a large, deep saute pan over medium heat, melt the butter. Add the leeks and shallots and sweat the leeks and shallots for 3 minutes, stirring occasionally. Season the mixture with salt and pepper. Add the wine and bring to a simmer and let the wine cook all the way down until it is almost cooked out. Add the stock and repeat the reduction process. Add the cream and reduce the heat to medium-low and let simmer until the leeks and shallots are tender and the sauce begins to thicken. Season the mixture with salt, and pepper again, if needed.

To plate:

Slice the steak into thin slices. Make a bed of mushrooms on each plate. Top with slices of steak and a piece of fish. Spoon the leeks on the side. Top the steak and fish with the red wine sauce.