Roast sea bass and potato traybake

Method

1. Heat the oven to 180°C/160°C fan/gas 4. Put the potatoes in a pan with salted water, bring to the boil, then cook for 15-25 minutes until tender.
2. Drain, then leave in the colander for a few moments to steam dry. Tip the potatoes onto a board, then give them a bash with a heavy object (I use the base of the pan I cooked them in). Don’t mash them, just bash flatter, exposing the flesh to maximise their crisping potential.
3. Trickle half the olive oil into a large roasting tray. Distribute the potatoes evenly on the tray. Scatter over the zest, fennel seeds and garlic, then season with salt and pepper. Trickle over the remaining oil, then roast for 45-60 minutes or until the potatoes are crisp and crunchy.
4. Meanwhile, make the pesto. Set a dry frying pan over a medium heat and toast the sunflower seeds for a few minutes, stirring regularly, until fragrant. Leave to cool, then pulse/ pound to a fairly fine consistency in a mini food processor/pestle and mortar with the garlic, cheese and some salt. Add the basil, then pulse/pound again until well chopped. Gradually pulse/stir in the oil. Once everything is combined with an even texture, check the seasoning, then spoon the pesto into a bowl (or see Make Ahead).
5. Cut the sea bass fillets widthways into 5cm pieces. Remove the potatoes from the oven, coat the fish pieces in the lemony garlicky oil, then arrange skin-side up, on and around the spuds. Roast for 8-10 minutes more or until the fish is just cooked through.
6. Remove the tray from the oven. Spoon the pesto over the potatoes in generous dollops, then scatter with the shaved pecorino and rocket. Serve the whole tray at the table.