Mix the garlic sauce with the olive oil, add salt and cayenne pepper and mix well with the yogurt. Finally, add the washed, torn parsley and the lemon or lime zest as desired.
Annotation:
If you add half a, finely diced (or, without the inner workings, coarsely grated) cucumber and a little fresh, finely plucked mint - you have a refreshingly delicious Turkish cacik or a Persian mast o-khiar.