Meanwhile , heat the oil in a large shallow saucepan. When the oil is hot add the asparagus, season with a little salt, saute, stirring frequently, until they just begin to take a little colour, approx 2 minutes. Add the garlic, lemon zest and chilli and continue to cook for 30 seconds. Remove from the heat.

Towards the end of the pasta cooking time remove approximately 75ml of the pasta water. Now return the asparagus to a gentle heat and add the lemon juice.

Drain the pasta and give it a good shake. Quickly tip the cooked pasta onto the asparagus and stir, add some of the pasta water, rocket and the parmesan. Cook, tossing the pasta vigorously and adding more pasta water if needed, cook until the sauce is creamy and emulsified and pasta is coated, about 1 minute.

Portion out into the bowls and place the egg yolk on the top. serve immediately.