Ingredients Substitutions

My paternal grandmother was known for her great culinary skills. So some of her neighbors had asked her for her most famous recipes. But after they tried to recreate them they could not get the same scrumptious results. They came to my grandma."Did you use the ingredients I listed?" my grandma asked and it turned out they substitute Mayo for Sour Cream, Milk for Kefir and so forth. Important lesson from that story is that if you want to recreate a recipe you are interested in --Do not substitute. Otherwise the taste might suffer and you might end up with completely different dish that  the one you have envisioned.