Heat oil in a large wok or frying pan on medium-high heat. Add onion and cook until softened, about 3 minutes.
Add garlic, garlic, and chili peppers and cook for another 1 minute.
Add coconut milk, stock, and fish sauce and stir well. Bring to a boil then reduce heat to low. Cook for 5 minutes until it reduces slightly.
Add prawns, lemon juice and stir together. Cook for 5 more minutes or until prawns are cooked through and opaque. Taste and add salt, pepper and chili flakes to taste. Serve with cauliflower rice.
