I just analyzed 1.9M recipes and can now report that the yummy simplicial complex is arguably *not* flag. The following flavor trios have far fewer recipes containing all three ingredients than the recipes with pairs of ingredients would predict.
An open problem in culinary mathematics: Consider the ๐ฆ๐ข๐๐๐ฆ ๐ ๐๐๐๐๐๐๐๐๐ ๐๐๐๐๐๐๐ฅ Y on vertex set I = {ingredients} where ฯโY iff the ingredients in ฯ appear in a single good recipe. Question: Is Y a flag simplicial complex? (A complex Y is ๐๐๐๐ when ฯโY iff {x,y}โY for all x,yโฯ.)