- 12 small (1-inch) yellow skinned potatoes
- 2 tablespoons butter
- Sea salt
- 4 half-inch-thick slices French bread or good-quality white bread, crusts trimmed
- 2 tablespoons butter, plus melted butter for brushing bread
- About 2 tbsp. olive oil
- 4 one-inch-thick beef tenderloin steaks (tournedos)
- Salt and pepper
- 3/4 pound crimini or white mushrooms, quartered
- 2 large shallots, chopped
- 2 cloves garlic, finely chopped
- 1 rounded tbsp. tomato paste
- 1/2 cup dry sherry mixed with 1 rounded tsp. cornstarch
- About 1/2 cup beef stock
- 2 tablespoons fresh tarragon, chopped
- 2 tablespoons olive oil
- 1 clove garlic, minced
- 4 cups (packed) baby spinach or baby kale
- 2 cups (packed) arugula
- Salt and pepper
- Juice of 1 small lemon (about 3 tbsp.)
Preheat the oven to 350 degrees.
Place the potatoes in a medium pot; cover with water. Bring the water to a boil, salt it and cook the potatoes until tender, about 12 minutes; drain. Using the bottom of a glass, gently press on the potatoes to crack and flatten them. In a nonstick skillet, melt 2 tbsp. butter over medium. When it foams, add the potatoes. Cook until browned and crispy, 3 to 4 minutes per side. Sprinkle with sea salt.
On a baking sheet, brush the bread with some melted butter. Toast in the oven, turning once, until light golden, 10 to 12 minutes.
While the potatoes brown and the bread toasts, heat the olive oil, two turns of the pan, in a cast-iron or other heavy skillet over medium high. When the oil smokes, season the steaks with salt and pepper and add to the skillet. Cook until browned and caramelized, about 3 minutes per side. Transfer to a plate and cover with foil to keep warm. Melt 2 tbsp. butter in the same skillet. When it foams, add the mushrooms. Cook, stirring occasionally, until browned, about 7 minutes. Add the shallots and garlic and stir until aromatic, 1 to 2 minutes; season. Add the tomato paste; stir to heat it, about 1 minute. Add the sherry mixture. Bring the sauce to a bubble, add the stock and simmer until thickened, 1 to 2 minutes. Add the tarragon; remove from the heat.
In a large skillet, heat the oil, two turns of the pan, over medium-high. Add the garlic and stir until aromatic, about 1 minute. Add the greens, season, then turn off the heat and toss until the greens wilt, about 2 minutes. Douse the greens with the lemon juice.
Divide the toasts among plates. Top with the steaks and saucy mushrooms. Serve each portion with 3 crispy potatoes and some greens.