Mushroom and Watercress Stirfry

Name: Mushroom and Watercress Stirfry
Ingredients: * 6-7 small button mushroom, halved; * 1 bunch watercress leaf; * 1 tomato, chopped; * 1 capsicum, chopped; * 2 shallot, halved; * 1 clove garlic; * 1 tbsp sunflower oil; for the sauce; * 4 tsp fish sauce; * 3 tsp jaggery (substitutes: palm sugar or brown sugar); * 1/2 cup boiling water