Photograph: Jonathan Gregson
For the stew, heat the olive oil in a large pan and gently cook the fennel and onions for about 20 minutes on a low heat until very soft. Finely chop the garlic, anchovy and chillies. Toast the fennel seeds in a dry frying pan until fragrant; set aside.
Add the chopped garlic, anchovies and chillies and the fennel seeds to the fennel and onions. Increase the heat and cook for a few minutes, stirring all the time.
Add the tomatoes, wine and 300ml water; season and bring to the boil. Simmer, stirring occasionally, for about 10 minutes.
To make the pangrattato, whiz the stale bread in a food processor to breadcrumbs. Heat 2 tablespoons of the olive oil in a large frying pan. Add the garlic, chilli and parsley, and cook over a high heat for a couple of minutes, stirring all the time. Add the breadcrumbs and, keeping the heat high, stir constantly until the breadcrumbs are crisp and golden. Tip into a bowl and add a few gratings of lemon zest; season. Wipe out the pan with kitchen paper.
Cut the fish into chunks. Add the fish chunks, mussels, prawns and chickpeas to the tomato sauce; gently stir to combine. Turn up the heat to high, then cover and cook for 5 minutes until the fish is just cooked through.
Meanwhile, bring a large pan of salted water to the boil. Blanch the broccoli for about 2 minutes – you want the florets to still be a little crunchy; drain. Heat the remaining olive oil in the cleaned frying pan, add the broccoli and a splash of water and stir until hot. Tip into a serving bowl and sprinkle with the pangrattato.
Once the fish is cooked, discard any mussels that don't open. Stir in the lemon juice and chopped parsley. Transfer to a serving dish and serve with the broccoli pangrattato and plenty of crusty bread.
Get ahead: make the stew up to the end of step 3 up to 3 days ahead; chill. Make the pangrattato a day ahead; store in an airtight container. Blanch the broccoli a few hours ahead.