Boil the shallots with the red wine vinegar in a heavy small saucepan until the vinegar is reduced to a glaze. Add the wine and boil until the sauce is syrupy. Add the chicken stock, garlic and soy sauce and boil until it has reduced and thickened to a sauce-like consistency. Season with salt and pepper. (This can be prepared ahead, cooled, covered and set aside at cool room temperature for several hours or refrigerated.) Preheat the oven to 300 degrees F. Season the steak with salt and pepper. Place a heavy cast iron skillet over medium-high heat and film with oil. Sear and place in oven until medium rare. Remove steak from pan and let it rest 5 minutes. Meanwhile add shallot glaze with butter to skillet to deglaze. Slice steak crosswise on the diagonal. Overlap the slices on a plate and pour the glaze over the steak. Serve immediately with frites.
Place the potatoes in a large bowl of cold water. Change the water repeatedly to remove the potato starch, until the water remains clear. (This can be prepared ahead to this point and set aside at room temperature in the bowl covered with cold water. Drain before cooking.) Dry the potatoes well in a lettuce spinner and a clean bath towel. To cook the first time, line 2 large baking sheets with paper towels. Heat the oil to 350 degrees F in a wok or large pot. Fry the potatoes in small batches without crowding until completely cooked, but barely colored, turning occasionally. Transfer to the prepared sheets in a single layer using a slotted spoon. (This can be prepared ahead and set aside at room temperature.) Preheat the oven to 200 degrees F. Line another baking sheet with paper towels. Reheat the oil to 350 degrees F. Fry the potatoes in small batches until crisp and golden brown, turning occasionally. Transfer the cooked potatoes to the prepared sheet using a slotted spoon and keep them warm in the oven while cooking the remaining potatoes, sprinkle with salt. Serve immediately. Yield: 2 servings