Season the tuna with salt and pepper and set aside. Combine the oil, thyme, lemon, garlic, red pepper and shallots in a large saucepot. Warm the oil over medium heat until it reaches 130 degrees F. Let the flavors steep for 10 minutes. Re-test the temperature, adjusting the heat, if necessary. Submerge the tuna in the olive oil poaching liquid and cook until it is firm and medium-rare, approximately 5 minutes.
Remove the tuna from the oil. Slice each piece. Arrange the tuna medallions over stewed lentils accompanied by sauteed broccoli rabe. Serve seasoned with Fleur de Sel and moistened with the olive oil poaching liquid.
Place the lentils in a pot. Add enough cold water to cover them by 2 inches. Season the water with salt then simmer the lentils over medium-high heat, stirring frequently, until the lentils are chewy, about 15 minutes. Drain the lentils and reserve.
Heat the olive oil in a medium pot, over medium-low flame. Add the shallots, garlic, crushed red pepper, and rosemary. Cook stirring frequently until the shallots and garlic are golden, about 10 minutes. Add the tomato puree and cook until it begins to concentrate, about 7 minutes. Then add the lentils. Stew the lentils in the sauce over a very low flame until they are fully tender but still holding their shape, about 10 minutes. Serve warm.
Think of the olive oil and herbs in this case as a tea. The basic idea of this dish is to have the cooking temperature very low. The tuna's exterior cooks while the interior maintains a consistent temperature. I find that this method avoids the metallic taste found in seared tuna.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Scott Conant, copyright 2004