
Heat oven to 400°F. Melt butter in a saucepan, add thinly sliced onion and cook 5 minutes until soft.
Add broth, Worcestershire and thyme and simmer 5 minutes for the dipping jus.
Drop the roast beef into the hot jus for 1 minute to warm, then lift it out with tongs.
Split the rolls, pile in beef and onions, top with provolone, and bake on a sheet pan 4-5 minutes until the cheese melts and the bread is toasty.
Serve each sandwich with a small cup of jus for dipping.
Photo: DinnerDrop