1.Heat oil in a non-stick large frying pan. Add onion, cook over a low heat, stirring, 5 minutes, or until soft but not coloured. Add garlic, cook, stirring, 1 minute, or until fragrant. Transfer to a bowl.
2.Cook pasta in a large saucepan of boiling salted water until just tender, drain. Return pasta to pan.
3.Meanwhile, heat the original frying pan. Add bacon, cook, stirring, until browned lightly. Transfer bacon to bowl with the onion.
4.Combine cream and egg yolks in a medium bowl. Season with sea salt and freshly ground black pepper.
5.Add bacon mixture and egg mixture to pasta, toss to combine. Sprinkle with half the parmesan and stir through.
6.Spoon pasta into serving bowls. Sprinkle with remaining parmesan, chives and freshly ground black pepper. Serve immediately with salad, if desired.