1. Place coconut milk in a small bowl; stir with a whisk. Reserve 1/4 cup; refrigerate.
2. Combine remaining coconut milk, stock, and next 5 ingredients (through peas) in a blender; process until smooth.
3. Ladle soup into shallow, chilled bowls if serving immediately, or transfer to a bowl and cover to chill. Garnish with reserved coconut milk and small basil leaves.