Combine the marinade ingredients and the cubed beef in a large bowl. Then cover with cling wrap and allow to marinate for 20 mins.
Make the salad dressing by combining the sugar and hot water in a bowl. With a spoon, dissolve as much of the sugar as possible.
Add the remaining dressing ingredients and combine thoroughly. Cover with cling wrap and set aside.
Prep all your vegetables. For best results, spin dry the watercress / salad mix after washing.
Heat a pan on medium - high heat and add vegetable oil. Fry the beef cubes to desired state. I like mine medium, so roughly 5-6 mins. (Note 2)
Place the watercress / salad mix, tomatoes, red onion and green apple in a large bowl.
Just before serving, spoon half of the dressing into the salad and toss.
Check the salad for seasoning. Add more dressing if needed and serve the remaining dressing in a bowl for anyone who wants additional sauce.
Place the salad on a plate with the beef cubes on top and serve with rice.