2.Heat oil in a large frying pan on medium. Saute fennel and onion for 5-8 minutes until tender. Add garlic and cook for 1-2 minutes.
3.Stir in cherry tomatoes. Season to taste. Spoon mixture into a shallow casserole dish.
4.Bake, covered, 15-20 minutes until sauce begins to thicken.
5.Stir fish into tomato mixture. Scatter lemon, olives and capers on top. Bake, covered, for 10-15 minutes, until fish flakes easily when tested with a fork. Serve with steamed spinach.
If you can’t find canned cherry tomatoes, use halved cherry tomatoes with 1 cup passata.