1 Smash up the garlic with 1 tsp salt in a pestle and mortar (if you don't have one, just finely chop the garlic).
2 Place the egg yolk and mustard in a bowl and whisk. Start to add your olive oil bit by bit. Once you've blended in 1/4 of the olive oil, start adding the rest in larger amounts.
3 When you've added it all, you can add the garlic and lemon to taste, and any extra flavours such as basil, fennel tops, dill and chopped roast nuts. To finish, season to taste with salt, black pepper and lemon juice.