This was a delicious bake, use homemade or store bought bechamel sauce.
Broccoli and Smoked Mackerel Gratin (from The Guardian)
375g smoked mackerel
2 large tomatoes, quartered
500ml bechamel sauce
4 handfuls fresh breadcrumbs
4 tbsp grated parmesan
Bring a large saucepan of water to the boil. Add the broccoli and leave to cook for 3-4 mins until bright and still a little crisp. Drain and cool under cold running water, then set aside. Set the oven at 180C.
Remove the skin from the smoked mackerel and break the flesh into large pieces, removing any bones as you go. Put the smoked mackerel, drained broccoli and tomatoes into a shallow ovenproof dish or baking tin.
Pour over the béchamel sauce, scatter with the breadcrumbs and Parmesan. Bake in the oven for 45 mins or so, until crisp and bubbling.