Peel and finely chop the garlic. Wash the chilli, carve lengthwise, remove seeds and cut into rings. Clean the shrimps, leaving the skin on the tail. Wash the shrimps and dab dry.
Clean, wash and chop the spring onions. Blanch briefly in boiling salted water, drain. Heat the oil, fry the garlic and chilli in it. Add the prawns and fry them for about 3 minutes, turning.
Season with salt, lime juice and soy sauce. Stir 3 tablespoons of fish stock and rice starch until smooth. Add the rest of the stock and soy sauce to the prawns and bring to the boil. Thicken with rice starch.
Warm spring onions in it. Season to taste again. Garnish as desired with coriander, chives and limes. Serve with rice.