To make the gratin, preheat the oven to 200C/400F/Gas 6.
Simmer the cream, garlic and potato in a small saucepan for five minutes. Season well and transfer to a gratin dish.
Sprinkle over the Edam and bake for 12 minutes.
To make the spinach, heat the vegetable and sesame oil together in a medium frying pan. Add the spinach and wilt down. Add the lemon juice and set aside.
To make the dressing, mix together the vegetable oil, sesame oil, soy sauce and orange pepper.
To make the tuna, heat a griddle pan over a high heat until smoking.
Rub the tuna with the oil and season well. Place the tuna upon the griddle and sear for one minute on each side.
Add the lemon juice with care as it may flame.
Serve the tuna on the wilted spinach. Drizzle over the dressing. Serve the gratin aside.
