Finely chop the main body of leeks, saving the tops for later (the green part at which the leaves fan out).

Meanwhile, heat a large heavy-bottomed pan over a medium heat and add a drizzle of olive oil and 25g of the butter. Once hot, add the shallots and chopped leek and fry for 15-20 minutes, stirring frequently, until soft and translucent. Add the garlic and fry for a further minute or so, just to soften.

Add the rice and a pinch of salt into the softened veg and stir to coat. Cook for a further 2 minutes, or until the rice turns mostly translucent. Pour in the white wine and allow to simmer and bubble for 2-3 minutes, until almost evaporated.

Add a ladleful of the hot stock into the pan and stir continuously. Once all the liquid has been absorbed into the rice, add another ladleful of stock. Repeat this step, stirring continuously between ladlefuls of stock, until the rice is creamy but still slightly al dente (if you run out of stock, you can either make up a little more or just use boiling water from the kettle).

Meanwhile, slice the tops of the leeks into long thin strips. Heat 2cm of vegetable oil in a pan over a medium-high heat. Once hot, add the sliced leek tops in batches and fry for a minute or so, until nice and crispy.

Remove the risotto from the heat and stir through the remaining butter, to melt. Taste and adjust the seasoning, if needed. Ladle into bowls and serve topped with the crispy leek tops, toasted hazelnuts, a drizzle of truffle oil and a good grating of lemon zest.