In a food processor, combine lemongrass, garlic, onion, green chillies, ginger, fresh coriander, lime zest, ground cumin, ground coriander, yoghurt and soy sauce.
Blend until you have a smooth paste. You may need to scrape down the sides of the processor to ensure everything is well mixed.
For the Green Curry:
Heat a large pan or wok over medium-high heat. Spritz with some low calorie cooking spray.
Add 2-3 tablespoons of the green curry paste (you can store the rest in an airtight container in the fridge for later use).
Sauté the paste for a couple of minutes until fragrant.
Add the coconut milk and vegetable stock. Stir well and bring to a simmer.
Add the salt, red bell pepper and onion. Simmer for 5-7 minutes, or until the vegetables are tender but still crisp.
Add the shrimp or prawns and cook for 2-3 minutes, or until they turn pink and opaque.
Sprinkle in some fresh basil leaves and serve with white rice.