Step 1: To prepare peanut sauce, combine 1/4 cup water, 1 tablespoon brown sugar, 3 tablespoons chunky peanut butter, 1 teaspoon Sriracha (hot chilli sauce – add to taste), and 1 teaspoon soy sauce in a medium bowl, stirring well with a whisk. Set aside.
Step 2: To prepare stir-fry, combine 2 teaspoons sugar, 5 teaspoons soy sauce, 1 teaspoon Sriracha (to desired taste), and 4 chopped garlic cloves in a small bowl, stirring with a whisk.
Step 3: Heat a large heavy pan over medium-high heat. Add 1 tablespoon sesame oil to pan. Add 230 grams tempeh (or extra-firm tofu) and ½ soy sauce mixture. Fry for 5 minutes or until tempeh is golden brown. Remove tempeh mixture from pan, and set aside.
Step 4: Add 2 teaspoons sesame oil to pan. Add 2 cups thinly sliced carrot, 1 cup capsicum strips, and 2 cups green beans to pan. Stir-fry 3 minutes. Add 1/2 cup water, reduce heat to medium. Cover and simmer for 5 minutes or until beans are crisp-tender. Stir in remaining soy sauce mixture, tempeh mixture, ½ cup chopped spring onions, and ½ cup mung bean sprouts. Cook for 2 minutes or until sprouts are tender. Serve with peanut sauce and garnish with chopped spring onions.