Making aioli is funny. It’s simple and fairly easy, but does require some strict guidelines. People tend to get religious about what goes into a good aioli and I didn’t really understand that until I started making it by hand myself.
Step 1: Make sure you’re completely alone. The more eyeballs pointed at the aioli, the more likely it’s going to break.
Step 2: Crush one clove of garlic and a pinch of salt in your mortar. If you don’t have a mortar, a metal bowl would work second best, and then a ceramic bowl last. I like to use something that has a rough texture inside because I think it aerates the aioli better.
Step 3: Add in an egg yolk and stir, incorporating it into the garlic paste. You can use the pestle, but I find a fork or a small whisk goes faster.
Step 4: Add in your oil* drop by drop while stirring at first until the mixture looks glossy. Once it’s glossy, you can start adding oil in a thin stream while stirring**.
* I like to use a mixture of extra virgin olive oil and a more mild oil like canola. I know the traditional provencal way is to use all olive oil, but sometimes I don’t want the olive oil taste to overpower the whole thing.
** Maybe this is living on the edge, but I let the stream drip into the mixture until it looks like it’s almost about to break. Then I stop the oil and stir quickly to incorporate. Then I repeat. If this sounds too risky, just add less oil at a time and stir for longer.
Since I never measure anything, I usually figure the aioli is done (has enough oil) when it’s the thickness I want and is a pale yellow color. I’ve never tried this, but if you want smoother, thinner texture, whisk in at most tablespoon of warm water, drip by drip.