Julia demonstrates how to work cold butter into dough, folding and layering the dough repeatedly to make French croissants. | Julia Child

Humans have likely been making gravy ever since they learned to cook—or overcook—meat. Fat starch stock = big flavor. Instant gravy changed the game in the 20th century by promising lump-free lusciousness if you, “Just add water!” This gravy from Panna Cooking changes it yet again, using stale croissants to provide the essential butter and flour: bit.ly/gravy-croissant | HISTORY