To make this recipe, start by preparing the creamy cashew sauce. Add all of the sauce ingredients (the soy sauce, hoisin sauce, rice vinegar, toasted sesame oil, ground ginger, cashew butter, and sriracha) to blender. Blend until smooth and creamy. If it's too thick, add in water, one tablespoon at a time, and re-blend until it reaches your desired consistency.
Next, prepare the steak. Add the trimmed flank steak to a large bowl and pour 1/4 of the sauce over top of it. Use tongs to coat the steak well.
Then, set the steak aside and allow it to marinate for 20-30 minutes. This is important, to ensuring that the steak takes on a rich and delicious flavor!
Then, one the skillet is very hot, add the steak to the pan. Do not touch the steak - allow it to cook for 4-5 minutes, undisturbed. Then, flip to the other side and cook for another 4-5 minutes, until the steak reaches an internal temperature of 135 F (for a medium-rare cook).
Once the steak reaches your desired level of doneness, remove it from the pan. Allow it to rest on a cutting board while you prepare the lettuce wraps.
Prepare the rice noodles according to the package instructions. Once they're done, set them aside.
Wash the carrots and cucumbers and chop them into matchsticks. Be sure to wash the lettuce leaves and mint and set them aside.
Once the steak has rested, slice it into strips, against the grain.
Finally, assemble the lettuce cups. Line the washed lettuce leaves up on a cutting board and layer the rice noodles evenly on top, followed by the cucumbers, carrots, mint, and slices of the steak.
Drizzle a spoonful of the Creamy Cashew Sauce on top.
Pour the remainder of the sauce into a small bowl to use for dipping.
Dip the lettuce wraps into the sauce and enjoy!