The cuisine is characterized by very little use of spices, little cooking over fire and strong flavours due mainly to the use of endemic exotic fruits and vegetables that are either fresh, dried or fermented. Fish is widely used, and birds like duck, squab, etc. are very popular, which are often paired with a main vegetable or ingredient. Preparations are rarely elaborate. (The practice of bhuna, the gentle frying of spices before the addition of the main ingredients so common in Indian cooking, is absent in the cuisine of Assam.) The preferred oil for cooking is the pungent mustard oil.