Database
[{"_id":"630875a5d0d70edb88e19a7b","favorites":[{"_id":"6309ef9e538eef79c9e53827","user":"6304d72e213e817ee090eb93","recipe":"630875a5d0d70edb88e19a7b"},{"_id":"630f1b5a8f00dfa9a7a5006c","user":"63066ce10722fdb443efb1f6","recipe":"630875a5d0d70edb88e19a7b"}]}]
Query
db.collection.aggregate([{$addFields:{favoritedUserIds:{$map:{input:"$favorites",as:"favorited",in:"$$favorited.user"}}}},{$addFields:{isFavorited:{$in:["6304d72e213e817ee090eb93","$favoritedUserIds"]}}},{"$unset":"favoritedUserIds"}])