Crush garlic cloves with half teaspoon salt. Place tahini in mixing bowl and beat well. This preliminary beating reduces the strong flavour of the tahini. Beat in garlic and vinegar. Gradually add lemon juice alternately with water. To make a cream salad of good consistency add enough lemon juice to make the tahini very thick before adding water. This way you have more scope in adjusting the flavour and consistency of the sauce. Add salt to taste, and more lemon juice if a sharper sauce is required. Blend in cumin and parsley and chill until required. Serve as a mazza or as directed in recipes. Makes about 1.75 cups