Add the lemongrass to the water and season with salt. Add the tripe and boil for about 1 hour or until tripe is tender. Remove from water and set aside.
Heat a sauté pan over medium-high heat. Cook the steak in pan until slightly pink, then remove to a bowl.
Thinly slice the cooked tripe into 2-inch strips and place in a bowl with the steak. Season the meat mixture with lime, toasted rice, ground chili pepper, sliced chili, MSG and fish sauce and stir to combine. Taste and season with more lime juice or fish sauce as needed. Add the cilantro and green onions and mix well.
Plate over bed of lettuce leaves, sprinkle with the mint and serve.
Recipe courtesy of The Today Show (NBC-TV, USA) Photo credit: Nathan Congleton / TODAY