Heat the olive oil in a large saucepan over a moderate heat until hot.
Sweat the fennel with some salt for 3-4 minutes, stirring frequently. Cover with a lid, reduce the heat and cook for 10 minutes until soft. Add the prawns once the fennel is soft and cook uncovered for 3-4 minutes until pink and tender. Spoon the prawns and fennel into serving bowls.
Drizzle with the extra-virgin olive oil and some soy sauce. Garnish with a sprinkle of sesame seeds. Serve immediately.