Makes 4 servings. Difficulty
4 teaspoons extra-virgin olive oil 1 onion, peeled and sliced 1/4 inch thick 2 medium zucchini, trimmed and sliced diagonally into 3/4 inch thick slices 4 large shiitake mushrooms sliced 4 filet mignons (about 1-1/2 inch thick)
Salt and freshly ground black pepper
1 cup dry red wine 1 cup balsamic vinegar 2 shallots, cut in half 1 garlic clove, smashed 3 fresh sage leaves 1 Tablespoon unsalted butter, cut into two pieces
Preheat oven to 200°F.
Place a heavy skillet over high heat. When hot, add 2 teaspoons olive oil. Place the onions in the skillet and cook until lightly charred on each side (not blackened). Transfer the onion rings to paper towels. Season the zucchini with salt and freshly ground black pepper. Add another teaspoon olive oil to the pan. When hot, add the zucchini, in a single layer. Sear zucchini until browned in spots on both sides. Transfer zucchini to paper towels. Add the shiitakes to the pan. Cook the mushrooms until softened. Transfer to a plate. Place vegetables in the warm oven to keep warm.
Brush or spray the filets with the remaining olive oil. Season both sides with salt and freshly ground black pepper. Add the steaks to the hot skillet; sear the meat 4 minutes per side (for medium-rare) or to taste. Transfer the steaks to a plate and tent with foil to keep warm. Place in oven to maintain warm temperature.
Return the skillet to the heat and add the wine. Deglaze the pan by scraping up any browned bits on the bottom of the pan. Add the vinegar, shallots, garlic and sage leaves. Cook sauce over medium-high heat until reduced to about 1/3 cup. Remove from the heat. Discard the shallots, garlic and sage leaves. Whisk in the butter. Adjust seasonings to taste with salt and freshly ground black pepper.
To serve, arrange 3 zucchini each on the center of 4 warmed dinner plates. Place 3-4 onion rings over the zucchini. Place a filet on top of the onions. Spoon about 2 tablespoons of sauce around each fillet. Top with a few more onion rings and a few shiitakes. Serve.