A popular fermented vegetable is prepared by allowing fresh leaves of mustasa (mustard) to wilt under the sun for two hours. Salt is then sprinkled on top of each leaf and the leaves arranged in layers in an earthen container. Use about 1/2 cup salt for every kilo of leaves. Rice water is then poured to cover the layers of leaves. The mouth of the container is then covered with cheesecloth or sinamay to prevent any insect from entering. Let stand for seven days. It is then ready for consumption.
The juice of the preparation is very sour. This can be used in preparing sinigang.
The burong mustasa may be prepared as:
Salad - wash the leaves once in cold water. Slice crosswise and serve with fresh tomatoes and onions.
Vegetable for sinigang - no need of washing. Use whole leaves as vegetables.
Omelet - wash and slice crosswise. Sauté with onions and tomatoes. Add beaten eggs last.