Preheat oven to 200C/400F on fan-bake.

Remove peas from freezer and set aside in a bowl at room temperature.

Thinly slice chorizo into 1/2cm/1/4in slices. Set aside. Slice the white part of the leek (discard the green part or use it for stock) in half lengthways. Give it a really good clean in cold water to remove any dirt or grit then finely slice across the leek. Set aside.

Drizzle olive oil in an oven-proof saucepan or Dutch Oven (I like to use my cast-iron enamel Le Creuset pot for this) over medium-high heat. Add chorizo and cook for about 5 minutes until browning and starting to crisp. Remove with a slotted spoon and set aside on a plate lined with absorbent paper towels.

Reduce the heat to medium, add sliced leek and cook until soft, about 5 min. Remove the pot from the heat and add garlic, saffron, chilli (optional), rice, wine, and 4 cups of stock. Cover and place in the oven for 15 min. Remove, stir, cover again and return to the oven for a further 10 min. Remove again, stir through the peas and cover. Return to the oven for another 5 min or until the rice is tender and the liquid is absorbed.

When the risotto is cooked, remove from oven and stir through remaining 1 cup of chicken stock, 20g/0.7oz of butter and grated parmesan cheese and stir vigorously until creamy. Gently stir through the chorizo, or scatter on top. The residual heat of the risotto will heat the chorizo or if you like you can put it in an oven proof dish and place it in the oven for 5 min when you add the peas to the risotto. Serve immediately with extra grated parmesan cheese.