This is a basic Mongolian lamb recipe. Original recipe had cucumber slices as garnish also. Any nice cut of lamb works well, you may want to bi carb any tougher cuts to soften before marinating.
For a beef version swap chicken stock for beef and i add black fungi, which seems to work well with steak. This recipe could be simplified by using a frozen Asian stir fry veg mix and jarred garlic and ginger, though the flavour will not be as good particularly the ginger. Please remember a recipe is just a guideline