Preheat the oven to 200°C fan/220°C/gas 7. Mix together the broccoli florets, onion, olive oil, garlic, chilli flakes and sea salt in a roasting tin, then transfer to the oven and roast for 10 minutes.

Stir in the orzo and the vegetable stock, cover carefully with foil, then return to the oven for a further 15–20 minutes, until the stock is absorbed. Pop the walnuts on a baking tray in the oven for the last 5 minutes to toast.

Remove the foil from the orzo and stir in the Parmesan, lemon zest and juice. Season with more sea salt as needed. Stir in the spinach, then scatter over the toasted walnuts and serve.

Note: If you know your chilli flakes are quite hot, use ½ teaspoon.