Put the oil, garlic and a good pinch of salt in a saucepan and heat until it reaches about 100°C.
Let the garlic simmer in the oil for about 5 minutes, then turn off the heat and let the oil cool thoroughly with the garlic still in it.*The garlic must not brown – if it starts turning golden, take the pan off the heat and simply let it cool.
Pour everything into a mini chopper and blend until the garlic is thoroughly puréed. Season to taste with salt.
Store the oil in the fridge. *See the introduction for how long it keeps.