The key to this dish lies in selecting the right ingredients that bring out the savory, juicy flavors without fuss. I always recommend using fresh, quality beef for the best taste—and don’t skimp on the broth for dipping. Growing up, my grandmother insisted that a good stock could transform any meal, and I couldn’t agree more. For the bread, something sturdy but soft inside works best since it soaks up the juices without falling apart.

• 1 pound thinly sliced roast beef (preferably from the deli or leftover roast)
• 1 sheet puff pastry, thawed
• 1 cup shredded Swiss cheese
• 1/2 cup caramelized onions (optional but highly recommended)
• 1 tablespoon Dijon mustard
• 1 cup beef au jus or beef broth
• 1 tablespoon butter (for sautéing onions)
• Salt and pepper, to taste
• Fresh thyme or rosemary, for garnish (optional)

Substitutions: You can swap puff pastry for crescent roll dough if you prefer a softer, fluffier texture. For a vegetarian twist, replace beef with sautéed mushrooms and use vegetable broth for dipping.