AUSTIN, TEXAS — Frozen foods are a “pandemic powerhouse,” growing 21% last year to $65.1 billion in retail sales, according to a report from the American Frozen Food Institute. However, the product developers at HumanCo believe much of the market remains ripe for reinvention. The first product offering from the company’s new Snow Days brand is an organic, grain-free pizza bite, a direct hit to General Mills’ piping-hot Totino’s business. “With Snow Days, we saw a great opportunity to disrupt a large and growing segment . . .