flank steak recipe, carmalized onion and mustard mixed with mayo
Place the marinade ingredients in a ziplock bag and marinate the flank steak at least 4-5 hour or overnight is best.
While the steak is marinating, make your caramelized onions. Heat a pan on medium-low heat, add the oil or butter, your sliced onions and sprinkle with the salt. Cook for 8 - 10 mins or until the onions get nice and browned and sweet. Stir every couple mins. Be careful not to burn them. Set them aside to cool.
When you are ready to cook your steak, heat your barbecue to medium-high heat. Wait for it to get nice and hot. So you can't hold your hand over the grill for more than a second.
Throw your steak on the grill and cook for 4 mins. Then turn slightly, a quarter turn, and cook for another 4 mins. This will get you beautiful criss-cross char marks on your steak. Then turn it over and do the same on the other side.
Take the steak off the grill and tent (cover) it with foil for at least 5 mins or up to 10 to let it rest and the juices redistribute.
With a sharp knife, slice the steak in thin slices against the grain.
When you are ready to make your sandwiches, put your oven on broil.
Make your sandwich by brushing the bottom of the bun with a little mayo (optional) then piling the steak on top, followed by the onions and the cheese on top of it all. Place the bottom halves on a tray and put them under the broiler for a couple mins until the cheese is all melted.
Spoon some mustard and mayo on the top half of the bun and place it on top of the melted cheese.