Boil the kettle. Drizzle the oil from the anchovy jar into a large frying pan, set over a medium heat. Add the anchovies and stir for a couple of minutes to break them up. Add the butter to the pan, swirling until it’s melted and foaming, then stir in the onions. Sizzle gently for 10 mins until the onions are soft, then add the garlic and preserved lemon and stir for another minute.

Fill a large saucepan with kettle-hot water, season with salt and bring to the boil. Add the pasta, cook for 5 mins, then tip in the broccoli and cook for another 5 mins, or until the pasta is cooked but still has a little bite. Scoop out a mugful of pasta water and set it aside, then drain the pasta and broccoli in a colander.

While the pasta cooks, heat the oil for the chilli crumbs in a frying pan and tip in the breadcrumbs. Stir regularly until the crumbs are golden and crispy, then add the lemon zest and chilli flakes.

Tip the pasta and broccoli into the anchovy sauce and add a good splash of the reserved pasta water and a squeeze of lemon. Cook for a few minutes, stirring, until it’s silky smooth and coats the pasta. Check and adjust the seasoning if necessary. Serve the pasta scattered with the crispy chilli crumbs.