Step 1

Heat 1 tablespoon of the oil in a medium frying pan over a low–medium heat and fry the squash for 20 minutes, until tender and lightly browned, turning regularly.

Step 2

Pour 1.2 litres/2 pints of water into a large saucepan and add the yeast extract, herbs and salt. Bring to a gentle simmer to make a quick stock, stirring occasionally. Leave to stand.

Step 3

While the squash is cooking, heat the remaining oil in a large, saucepan and fry the celery for 2 minutes, stirring. Add the rice and cook for 1 minute more.

Step 4

Stir in the wine and simmer until it has almost disappeared. Stir in the grated carrots and cook for a few seconds.

Step 5

Add a ladleful of the warm stock (around 100ml/3½fl oz) to the pan and cook, stirring regularly, until it has been absorbed by the rice . Continue adding the stock, stirring well between each addition. Cook, until the rice is tender and the sauce is creamy. This will take 15–20 minutes.

Step 6

Add two thirds of the Parmesan and spinach leaves, a handful at a time, and cook until the leaves are soft and the cheese has melted. Season with salt and pepper and stir in half the cooked squash.

Step 7

Spoon into serving dishes and top with the remaining squash. Sprinkle with the rest of the cheese and serve immediately.