[{recipe:"recipe1",ingredients:["1 cup cooked quinoa","6 tbsp butter","1 large egg"]},{recipe:"recipe2",ingredients:["2 lemons","2 tbsp butter","1 large egg"]},{recipe:"recipe3",ingredients:["1lb salmon","1 pinch pepper","4 spears asparagus"]}]

db.collection.find({$expr:{$eq:[{$size:{$filter:{input:"$ingredients",cond:{$regexMatch:{input:"$$this",regex:"lemons|butter|egg|milk|bread|salmon|asparagus|pepper",options:"i"}}}}},{$size:"$ingredients"}]}})