French Dip Sandwiches

I used to make these and take them to B. Bears football games- sooo good! Here's another really good beef sandwich.

1 teaspoon olive oil
1 onion halved and sliced thin
4 6inch sub rolls
2 tablespoons unsalted butter, softened
4 cups thinly sliced leftover roast beef
1 cup jus, heated in small saucepan Recipes follows
4 slices provolone cheese, cut in half

1. Position rack 6 inches below broiler. Heat in small nonstick skillet over medium-high heat until shimmering. Add onion and cook, stirring frequently, until browned, about 7 minutes.

2. Slice rolls in half lengthwise and spread with butter on both sides. Place rolls on baking sheet butter side up, and broil until golden brown, 1-3 minutes. Removed top half of each roll.

3. Using tongs-dip beef slices into hot jus and place about 4 slices beef on bottom half of each roll. Spoon onions over beef and arrange provolone on top. Broil until cheese is melted. Set top half of each roll in place and serve with extra jus for dipping.

Quick Jus

1 teaspoon olive oil
1/4 cup minced onion
1 teaspoon flour
3 cups low-sodium beef broth

Heat oil in medium skillet over medium-high heat until just smoking. Add beef broth and cook 1 minute. Reduce heat to medium, add onion, and cook until slightly softened