In a small bowl add the tahini and slowly pour in 60 ml of the water while whisking.
Add half the lemon juice while whisking. Keep whisking and continue adding a bit of the remaining lemon juice so that you achieve the desire density and acidity. It should be slightly thick, not running. Add more water only when the desired acidity has been achieved and you wish to reduce the density.
Add the garlic, salt and oil and keep whisking lightly. Garnish with the parsley and serve.