1/4 cup oyster sauce
1 scallion, white and green parts, thinly sliced on diagonal
Steamed jasmine rice, for serving
Heat wok over medium-high heat. Add oil and swirl to coat inside of wok. Add yellow onion and capsicums and stir-fry for about 3 minutes, or until onion begins to soften. Addchilli, garlic, and ginger and stir-fry for about 1 minute, or until fragrant. Add prawns and stir-fry for about 2 minutes, or until they begin to turn opaque. Add reserved sauce and peanuts and stir-fry for about 1 minute, or until prawns are just pink and cooked through.Stir in 3/4 cup of basil leaves.
Transfer stir-fry to platter. Sprinkle spring onion and remaining 1/4 cup basil leaves over and serve immediately with rice.