Put all the sauce ingredients, nut butter, soy sauce, sweet chili sauce, rice wine vinegar, white wine, tamarind paste, ginger and garlic in a heatproof jug and mix well.
Heat 1 Tbsp water in a pan with the spring onions.
Sauté over a medium heat stirring occasionally for five minutes, adding a little more water if it starts to stick.
Add the chili (if using) and mixed vegetables to the pan and continue to cook for another five minutes, stirring from time to time.
Add the greens and continue cooking until the greens soften, another five minutes or so.
Pour the sauce from the jug over the vegetables in the pan.
Rinse the jug with an extra ½ cup of boiling water from the kettle and add to the pan.
Stir to combine and continue cooking until the sauce is simmering, adding a little hot water if the vegetables need more.