Easy French Dip Sandwiches

We probably have these once a month...it is definitely a favorite. This recipe makes at the most 3 sandwiches. The ingredients will be in terms of what I buy at the grocery store. Let me know if it is a little confusing, we altered it from a Rachael Ray recipe.

Ingredients:
3/4 diced onion
2 swirls in pan of Extra Virgin Olive Oil
2 cans of beef broth
a package of sliced roast beef (or 3/4lb. roast beef from deli)
Sandwich rolls (we tried it last night with the Sara Lee rolls and they were tastier than baquettes)
1 package provalone cheese
1 package parmesan cheese

Directions:
Slice rolls in half, butter and sprinkle with parmesan. Put in oven on broil until cheese is melted or the bread looks toasted.
While toasting the bread saute onions in skillet with the 2 swirls of extra virgin olive oil. Once the onions are soft pour in the 2 cans of beef broth. Turn stove down to low-medium and start separating the roast beef and putting it directly in the broth.
At this point the bread should be toasted. Take out of oven but leave the oven on. Start taking the beef out of the pan and placing on one half of each roll. Top the beef off with the provalone cheese (it usually takes 2 slices). Put the rolls back in the oven, leaving the top of each roll off the bottom half so the cheese can melt. Once the cheese has melted remove from oven and start putting top of each roll on top of the cheese.
Now it is time to plate. Put some au ju in a bowl and slice the rolls in half. Enjoy!