Add the fish stock, coconut milk, chili paste, dried chili, basil leaves, and lemon juice, and season with salt and pepper to taste. Lower the heat and let simmer for about 10 minutes.
3 cups fish or vegetable stock, 2 cups coconut milk, 3 tbsp. chili paste, 1 tbsp. fresh lemon juice, 1 tsp. dried chili flakes, 2 to 3 fresh Thai basil leaves, Sea salt and freshly ground black pepper