Microwave cooking package

A microwave popcorn package comprising:

• a sidewall construction including a first side panel and a second side panel, the sidewall construction defining an interior between the first and second side panels, the first side panel and the second side panel joined at opposed side ends, the first side panel and the second side panel forming an opening between the opposed side ends, the sidewall construction being selectively expandable between a collapsed configuration and an expanded configuration, wherein the sidewall construction forms vertical sidewalls in the expanded configuration;
• a bag construction having a first bag side, a second bag side, and a bag base, a portion of the first bag side secured to the first side panel of the sidewall construction, a portion of the second bag side secured to the second side panel of the sidewall construction, the bag base extending between the first and second sides of the bag construction, the bag construction being selectively expandable between the collapsed configuration and the expanded configuration, wherein the first side, the second side, and the base of the bag construction define an interior, the base of the bag construction is configured within the opening formed by the first side panel and second side panel;
• and
• a popcorn charge disposed in the interior of the bag construction.