- In a glass bowl or in a sealable plastic bag, combine all of the ingredients. Set aside.
- In a skillet over high heat, brown the beef on all sides in the oil without overcooking the meat. Let cool for a few minutes. Place the tenderloin in the marinade and coat thoroughly. Cover the bowl or seal the bag and refrigerate for at least 4 hours or overnight.
- Remove the meat from the marinade and strain the marinade through a sieve.
- In a small bowl, combine the mayonnaise with 2 tbsp (30 ml) of the strained marinade.
- Thinly slice the meat against the grain and divide among plates. Serve with the lettuce and drizzle with the mayonnaise.
If you have leftover meat, serve it in a sandwich.