8 garlic cloves, peeled
1½ cups extra-virgin olive oil
1 tablespoon plus 1 teaspoon coriander seeds
2 teaspoons whole black peppercorns plus 1 teaspoon freshly ground black pepper, divided
2 teaspoons fennel seeds
3 tablespoons finely chopped fresh thyme leaves
4 fresh bay leaves
One 2-pound beef tenderloin roast (preferably center cut)
2 teaspoons kosher salt
2 tablespoons extra-virgin olive oil
2 cups wild mushrooms, trimmed into evenly sized pieces
3 sprigs fresh thyme
1 fresh bay leaf
1 garlic clove, smashed
½ teaspoon kosher salt
¼ teaspoon freshly ground black pepper
1 tablespoon unsalted butter
1. Make the marinade for the tenderloin roast: In a small saucepan set over medium heat, add the garlic and olive oil and cook until the garlic becomes golden, about 15 minutes. Turn off the heat.
2. In a medium skillet set over medium heat, toast the coriander seeds, whole black peppercorns and fennel seeds, shaking the pan often and cooking until the peppercorns are fragrant and the fennel seeds are golden, about 2 minutes. Turn off the heat and transfer the spices to a blender. Add the poached garlic and oil, chopped thyme and bay leaves and purée until smooth. In a resealable plastic bag, add the purée and the tenderloin roast. Seal the bag and use the bag to massage the herbed marinade into the meat. Refrigerate overnight.
3. The next day, preheat the oven to 350°. Remove the tenderloin roast from the bag, use paper towels to blot dry, then season with the salt and remaining 1 teaspoon of ground pepper. Heat a grill pan over high heat for 2 minutes, add the roast and sear on all sides until marked, 2 to 3 minutes per side (you can also sear the tenderloin roast on a charcoal or gas grill until marked on all sides). Transfer the roast to the oven and cook to your preferred degree of doneness, 22 to 25 minutes for medium rare (120° on an instant-read thermometer). Remove from the oven and set aside for 30 minutes to rest. Slice the roast crosswise into ¼-inch thick pieces.
4. While the roast rests, make the mushrooms: In a large skillet set over high heat, add the oil and heat until it begins to smoke, 2 to 3 minutes. Add the mushrooms, stir once, and cook without stirring until they begin to brown, 3 to 4 minutes. Stir in the thyme, bay leaf and garlic and then add the salt and pepper. Toss to combine. Add the butter, stir until melted, then serve the mushrooms over the steak.