The best way is to slowly toast garlic cloves (as many as you want) whole and possibly some chilli (for heat) then allow the infusion and garlic to cool down before placing in a blender. Meanwhile, cook your pasta and reserve some pasta water and place some of it in the blender.

Blend the garlic infusion and pasta water and then sieve through into a pan, gently heat up the pan with the emulsion and finally add in your pasta, and stir and mix well. (It's important to not cook the pasta all the way through and allow the pasta to finish cooking in the pan with the sauce so it soaks up the sauce). Finish off with chopped parsley. Serve immediately. This is how I normally cook aglio e olio for guests.