Bring a saucepan of water to the boil with salt, put in tagliatelle pasta.
Get a pan, heat the pan up on medium-low heat, add a tiny bit of oil, put in crushed garlic and basil leaves. After 2 minutes, add cream. Once it starts sort of boiling and changing colour, add pesto and stir well. Drain tagliatelle and put the tagliatelle in the sauce and stir again. Season with pepper.
Don't overcook the cream. You can see the cream changing colour and start to thicken and this is when it's ready for you to add the pasta and stir it in.