Heat the oven to 220C/190C fan/gas 6. Put the onion and potatoes in a roasting dish, drizzle with oil and top with the garlic. Season well with salt and pepper. Roast for 25-30 mins, turning halfway, until golden and cooked through. Remove the garlic from their skins and squeeze over the potatoes.

When the potatoes are cooked, mix the chopped canned tomatoes with a good pinch of salt and pepper. Scatter the olives, chilli flakes, capers and anchovies over the potatoes and mix well. Pour over the seasoned canned tomatoes. Nestle in the hake fillets on top.

Cover with foil, then return to the oven for 10-15 mins, until the fish is cooked. It should be opaque and flake easily when lightly pushed with a fork.

Scatter with the parsley and serve straight from the tray.