- In a bowl, combine the soy sauce, water, lime juice, brown sugar, hazelnut oil, sambal oelek and garlic. Reserve 1/2 cup (125 ml) of the mixture for serving.
- On a work surface, cut the tenderloin in half horizontally. Thinly slice both pieces, cutting against the grain of the meat.
- In a bowl, combine the beef with the remaining marinade. Cover and refrigerate for 1 hour.
- Drain the meat and reserve the marinade.
- In a skillet over high heat, working in batches, quickly brown the beef in the olive oil. Lightly season with salt and pepper. Transfer to a plate. In the same skillet, bring the reserved marinade to a boil for 3 to 5 minutes (make sure to boil it thoroughly, since it has been in contact with raw meat). Remove from the heat. Pour over the cooked meat and toss to combine.
- Arrange the lettuce leaves on a large serving platter. Top each leaf with slices of beef and pear, then sprinkle with the hazelnuts and green onion. Serve with the reserved sauce and steamed rice, if desired.