A thermally insulating packaging to hold an item includes a solid compostable or recyclable shell that is formed primarily of a plant fiber, and a bottom cover. The shell includes a floor, a plurality of inner side walls that are coupled to the floor, a rim coupled to the plurality of inner side walls, and a plurality of outer side walls that are couple to the rim. The floor and the plurality of inner side walls define an interior space of the shell to receive the item and an opening to the interior space. The plurality of inner side walls and plurality of outer side walls have a space therebetween that defines a gap. The gap can be an air-filled cavity, or be filled with a compostable or recyclable core material.