12Slider rollsI used sweet steakhouse rolls, can use hawaiian rolls
2red onions that have been caramelizedshortcut, saute’ instead
Place broth in a small sauce pan over medium high heat, bring to a boil, then turn down to a simmer. Cook until broth is reduced to ½ cup. Set aside
Assemble the sandwiches by cutting the rolls in half lengthwise, separating the tops from the bottoms. Place the bottom half of the rolls in the 9x13 casserole dish, then layer the beef, cheese, and onions.
Put the tops of the rolls on.
Melt the butter, and then add the broth, worcestershire, garlic powder and dijon mustard, whisk to combine well. Pour the mixture over the top of the sandwiches distributing it evenly.
Cover with foil and bake at 350° for 30 minutes.
Two sandwiches will serve one person if this is your main meal served with sides. One sandwich is good if you're serving a crowd as an appetizer where there are other appetizers as well.
Quick Cut Slider Roll Tip: Slider rolls are usually all stuck together when they come in the package. You can slice a knife through all of them lengthwise, so you’ll have one big ‘rectangle’ of rolls for the bottom halves and one for the top. Use a long serrated knife to do this if you have one.
To Caramelize Onions: Cook sliced onions in 1-2 tablespoons of butter over low heat. They take some time to turn brown and caramelize, 45 minutes to an hour. You can do this a day or two ahead of time and keep them in the refrigerator until you're ready to use them.
For a shortcut, you can saute' the onions over medium heat until they become translucent, about 7 minutes. They won't be as sweet as caramelizing them, but they are still delicious.