In a separate large bowl, mix the onions, scallions, cilantro, Old Bay seasoning and mustard. Stir in the crackers. Add the egg and milk mixture. Gently fold in the crab meat taking extra care not to break up the crab lumps. Cover and refrigerate for 1 hour.
Mold the mixture into 8 equal cakes and place them on a baking dish. Chill, again, for half an hour.
In a large heavy frying pan heat the oil and butter over medium high heat. Lightly dust the crab cakes with flour and place them in the frying pan. Cook on each side for four minutes or until golden brown.
Recipe by How To Crab at http://how-to-crab.com/crab-cakes/recipe-for-crab-cakes/