For the homemade prawn stock:

1. Peel and devein the prawns, reserving the head and the shells.
2. Heat a splash of extra-virgin olive oil in a medium saucepan over high heat. Add the prawn heads and shells and cook, stirring frequently, until they turn red and are very fragrant, 3 to 5 minutes. Use a potato masher to firmly smash the heads and shells – this will help release their beautiful flavour.
3. Add the remaining stock ingredients and stir to combine. Bring the stock to a simmer. Cover, reduce the heat to low, and simmer for 1 hour, stirring occasionally.
4. Strain the stock into a clean saucepan – that is, pass it through a fine mesh sieve, leaving the solids behind. Press down on the shells and vegetables to make sure you’re getting all of the liquid. Cover and keep the stock warm over very low heat.

For the risotto:

1. Heat a splash of extra-virgin olive oil in a large saucepan over medium heat. Add the onion and season with a generous pinch of sea salt. Cook, stirring occasionally, until translucent and softened, around 5 minutes. You want the onion to cook gently without it taking on any colour.
2. Add the garlic and cook for 1 minute, stirring constantly so it doesn’t burn, then add the risotto rice and stir well to coat in the oniony/garlicky oil. Cook, stirring constantly, until the rice begins to look slightly translucent, 2 to 3 minutes.
3. Add the white wine and cook, stirring frequently, until the pan is almost dry, 1 to 2 mins.
4. Add one ladleful of the hot homemade prawn stock and cook, stirring almost constantly, until the stock is fully absorbed. Add another ladleful of stock and cook, stirring almost constantly, until the stock is fully absorbed.
5. Repeat this process until the rice is cooked; it should be tender with a slight bite. The whole process should take around 25 to 30 mins and you should need anywhere between 750 ml and 1 litre of the homemade stock. The risotto should be loose, creamy and saucy.
6. Season the risotto with sea salt and freshly-ground black pepper, to taste, then stir in the prawns. Cook, stirring constantly, until the prawns are almost cooked through, around 2 minutes (they’ll finish cooking later). If necessary, add an extra ladleful of stock to ensure that the risotto stays nice and loose.
7. Remove the saucepan from the heat. Add the grana padano and stir well to combine. Cover the saucepan and allow the risotto to sit for 3 minutes before serving. You might be tempted to skip this step but don’t – this is when the risotto becomes deliciously creamy and where the prawns finish cooking.
8. Taste and adjust seasoning. Divide the risotto between bowls and serve with lemon wedges on the side for squeezing over – enjoy!