This is a recipe from my childhood. My mom would vary how she made it, when she had time, she actually washed & trimmed the watercress, when she was rushed she used bagged salad. Sometimes she made her own dressing, sometimes she used a bottle of Italian dressing. Both were delicious.
For this recipe I used watercress, and I made my own dressing with 1/4 c sesame oil, 1/4 c olive oil, 1/2 c rice wine vinegar, 1 tsp sugar, 1/2 tsp salt, & 1 tsp pepper. Wash & trim your watercress or pull your salad out of the bag. Toss with the dressing & let it marinate for a few minutes, while you cook a pot of rice.
Slice your beef really thin, I find it's easier to slice thin when it's slightly frozen. Slice an onion real thin & finely chop 2-3 cloves of garlic. Marinate all this in soy sauce & black pepper. I use Golden Mountain brand soy sauce.
Here's the easiest way to chop garlic:
^This man is a genius^
Cook the meat mixture until the onions are wilted. Serve on top of salad, over rice. The soy sauce mixture along with the dressing makes something spectacular happen in your mouth.