Method

• 1.
  Place egg, yolks and half the parmesan in a small bowl and gently whisk to combine. Season and set aside.
• 2.
  Bring a large saucepan of salted water to the boil over high heat. Add the pasta and return to the boil. Reduce heat to low and simmer for 4-5 minutes until just cooked. Drain pasta in a large heatproof bowl and reserve 1 1/2 cups (375ml) cooking water.
• 3.
  Scatter over half of the basil, half the butter and remaining 50g parmesan over the pasta. Season to taste and toss well to combine. Set aside.
• 4.
  Meanwhile, heat remaining butter in a large deep-sided frypan over high heat. Add the onion, garlic, bacon and remaining basil. Cook, stirring occasionally, for 5-6 minutes until onion is soft and bacon begins to brown. Reduce heat to low, scatter over the pasta and toss to combine.
• 5.
  Pour in the parmesan and egg mixture with the reserved coking water. Season to taste and toss until the egg and parmesan mixture has thickened and made a little sauce. Scatter over extra parmesan and basil leaves to serve.