Curried Pistachio Butter

• 3 tbsp. unsalted butter, at room temperature, plus ½ cup/115 g
• 1 cup/55 g fresh bread crumbs (see Cook’s Note)
• 3 tbsp. black sesame seeds
• 3 tbsp. unsalted roasted shelled pistachio nuts
• 1 tbsp. curry powder
• 1 tsp. kosher or fine sea salt
• 1 egg yolk
• One 1¾-to-2-lb/800-to-910-g beef tenderloin
• Kosher or fine sea salt
• Freshly ground pepper
• 3 tbsp. canola or other neutral oil
• 3 tbsp Fresh Wasabi Paste

1. To make the pistachio butter, in a medium frying pan, melt the 3 tbsp. butter over medium-high heat. Add the bread crumbs and sauté, stirring constantly, until crisp and golden brown, about 2 minutes. Transfer to a plate to cool. Put the sesame seeds on a small microwave-safe plate and microwave the seeds on high power until lightly toasted, about 4 minutes. Set aside to cool. (It is hard to tell with black sesame seeds when they are toasted because they are black! In my microwave oven, at 2 minutes they felt hot but not crisp, so I toasted them 1 minute longer, checked to make sure they weren’t burning, and then toasted 1 minute longer.)
2. In a food processor, combine the pistachios, sesame seeds, curry, and salt and process until the nuts are finely chopped, about 30 seconds. Cut the remaining ½ cup/115 g butter into thin slices and add to the processor along with the egg yolk. Process for 1 minute, stopping the machine once or twice to scrape down the sides of the work bowl. Scatter the bread crumbs over the top and pulse five or six times until incorporated. Spread a long sheet of plastic wrap on a clean work surface. Using a rubber spatula, form the butter into a log about 1½ in/3 cm. in diameter. Wrap the plastic wrap around the butter and roll to form a tight, compact log. Refrigerate until ready to use. (The flavored butter can be refrigerated for up to 5 days or frozen for up to 2 months.)
3. Remove the tenderloin from the refrigerator 1 hour before you plan to roast it. Position a rack in the center of the oven and preheat to 400°F/200°C/gas 6.
4. Rub the meat on all sides with some salt and pepper. Place a heavy, ovenproof 10-in/25-cm. frying pan, preferably cast iron, over high heat. When hot, add the oil and swirl to coat the pan bottom. Immediately add the tenderloin, rounded-side (top-side) down. Sear without moving the meat for 4 minutes. Turn and sear the second side for 3 minutes. Immediately transfer the pan to the oven and roast the meat for 15 minutes, and then check the internal temperature using an instant-read thermometer. Remove the meat when the thermometer registers 115° to 120°F/46° to 49°C for rare, 125° to 130°F/52° to 54°C for medium-rare, or 130° to 140°F/54° to 60°C for medium. (Keep in mind that the temperature of the meat will increase a few degrees once it is placed under the broiler.) Remove the pan from the oven and turn on the broiler. Adjust the oven rack if necessary, so the top of the tenderloin will be about 4 in/10 cm. from the heat source.
5. Spread the wasabi paste all over the top of the roast. Cut the log of pistachio butter into thin slices and lay the slices over the wasabi. Place the roast under the broiler and broil until the butter is crusted and turns deep brown, 3 to 4 minutes (The egg yolk in the butter keeps it from melting, forming a lovely crunchy crust.) Carefully transfer the roast to a carving board. Let the meat rest for 5 minutes to allow the juices to set. Carve across the grain into thick slices and serve immediately.