A bag for retaining the warmth and crispiness of food items contained therein is disclosed. The bag is made of cellulose-based, oven-durable outer and inner plies that are adhesively affixed together by adhesive layers, a bag interior defined by adjacent faces of the inner ply, and at least one pocket formed between the outer and inner plies defined by adjacent adhesive layers. The outer and inner plies are pierced with a plurality of apertures such that the apertures pierced within the outer ply are offset from the apertures pierced within the inner ply by a predetermined dimension. Due to a temperature differential, vapors emitted by a warmed food item inserted in the bag interior are driven into each one pocket and remain within the corresponding pocket for a useful period of time. A process for producing the bag is also disclosed.