I used this recipe for the cooking method, and used RasaMalaysia.com's ingredients since most of the reviews said it was bland. based on that recipe, I added fish sauce, rice vinegar, miso and a little hoisin. my family doesn't usually like it when i try to make international-inspired dishes, but they loved this.
https://rasamalaysia.com/black-pepper-beef/ for the recipe I used, or check under the "'fancy' foods" collection in my profile.
