Described is a rotary pan (1) of the type comprising a central hollow cylindrical body (3) with end portions (4, 4′) shaped substantially like truncated cones, and mixing/deflecting means (7) attached to at least one inside surface of the pan (1) itself; the peripheral inside cylindrical surface (5) of the hollow body (3) comprises an extended zone (A) defined by a uniform distribution of through holes (6) and at least one zone (B) within the zone (A) forming an area by which the mixing/deflecting means (7) are attached or fixed to the peripheral surface (5).