About this recipe: This is a popular Catalan garlic sauce that goes very well with grilled meat and roasted pepper and aubergine (Escalivada). I have seen many spellings for this (i.e. alioli, aioli...) but the real name is "All i Oli" - from the Catalan for Garlic and Oil - and these 2 are the only ingredients although there are variations and some places add egg to ensure the consistency of the sauce, which with our without egg should look like mayonnaise.
A trick to ensure that the mixture stays thick is to make sure the ingredients are at the same temperature when starting to make the sauce.
If too much oil is added, the mixture separates and you'll see the garlic floating in oil. Anyhow, if the ingredients separate for any reason (which I don't mind) and you don't like the look of it, add one egg and beat it all together and it'll be like a garlic mayonnaise.