Packaging in flexible material for food products to be consumed after heating in the oven

Packaging (10) in flexible material, comprising a supporting base (11) wherefrom two opposite side walls (12) rise up, each one sealed to a half-perimeter (13) of the base (11) and sealed one to the other along respective side edges (14) and along the upper edge with a head sealing (16), in an intermediate area of the packaging (10) at least one continuous transverse sealing (17) being provided, suitable for dividing the interior of the packaging (10) into two separate chambers, a lower chamber (20) and an upper chamber (21), suitable for containing two different components of a product to be brought into contact at the time of consumption, characterised in that said transverse sealing (17) is such as to open when a certain pressure is reached in said lower chamber (20), following heating, thus forming a single chamber inside the packaging (10) and in that at a short distance from said upper or head sealing (16) a second transverse head sealing (18) is provided, and between said head scalings (16, 18) at least one side vent or opening (19) is provided, said second transverse head sealing (18) being such as to open when a certain pressure is reached in said unified chamber (20, 21).