Put the flour onto the worktop and make a well in the middle
Add the eggs, oil and salt and mix in with the flour, first with a fork, then with your hands
Add the coffee a little at a time
Add water if needed to make an elastic dough. Roll out the dough very thinly, using some flour on the surface to stop it sticking, and leave for a few minutes, then roll loosely and cut the dough into strips (as wide as you like)
Boil the strips in plenty of water with a pinch of salt and while you wait for them to cook, prepare the sauce
Slowly melt the butter and add the cream to thicken the sauce
Add salt and freshly ground pepper to taste
Once you have drained the tagliatelle toss with the sauce and serve with a sprinkling of chives.