I remember the first time I tucked into a French Dip Grilled Cheese: the bread was gloriously crisp, the Swiss cheese pulled in long, gooey ribbons, and the warm au jus shimmered beside it like a savory little pond waiting to dunk into. This sandwich is everything I want on a chilly afternoon—comforting, indulgent, and a tiny bit theatrical when you pierce it and watch the steam rise.

Why French Dip Grilled Cheese deserves a permanent place on your menu

It combines two irresistible concepts: a classic grilled cheese and the soulful au jus of a French dip, giving you crunchy, gooey, and savory with each bite.
The caramelized onions add a sweet, deeply browned note that elevates the roast beef instead of competing with it.
It’s surprisingly easy to assemble, but feels special enough for guests or a cozy night in.
You get contrast in every forkful: crisp exterior, molten cheese, tender beef, and a fragrant broth for dipping.
Leftovers reheat beautifully, so it’s a win for both dinner and next-day lunches.

I often pair this kind of sandwich with a bright little dip or a sweet side; if you’re into quick and comforting nibbles, you might also enjoy a simple, crowd-pleasing option like 3-ingredient cream cheese fruit dip to balance the savory notes.

The ingredient rundown (and why each one matters)

8 slices crusty French bread — Provides a sturdy, crunchy shell that stands up to dipping.
8 slices Swiss cheese — Melts beautifully and offers a nutty, milky backbone to the sandwich.
12 ounces thinly sliced roast beef — The star protein; choose thin slices so they fold and warm through.
2 medium yellow onions, thinly sliced — Caramelize into sweet, jammy ribbons that add depth.
4 tablespoons unsalted butter, plus extra for spreading — For golden, crisp bread without getting salty.
1 tablespoon olive oil — Helps the butter and onions caramelize without burning.
2 cups low-sodium beef broth — Forms the au jus; low-sodium lets you control seasoning.
2 teaspoons Worcestershire sauce — Adds savory umami and a faint tang.
1 teaspoon soy sauce — Rounds out the broth with a touch of savory saltiness.
1 garlic clove, minced — Aromatic lift for the au jus.
1 sprig fresh thyme — Fresh herb perfume that pairs beautifully with beef.
Salt, to taste — For final seasoning adjustments.
Black pepper, to taste — Freshly cracked is best for a little heat and aroma.

If you like breakfast-for-dinner ideas, the rich cheese-and-bread combo here pairs nicely with brunch-style dishes such as a baked French toast casserole; I often think of recipes like blueberry cream cheese French toast casserole when planning a weekend menu.

Let’s get cooking — the exact steps to make it happen

Follow these numbered steps exactly to assemble the sandwich and au jus. You’ll be rewarded with crispy bread, melted cheese, and a warm dip that brings everything together.

In a large skillet over medium heat, melt 1 tablespoon of butter with olive oil.
Add sliced onions and sauté, stirring frequently, until deeply caramelized and golden brown, about 12 to 15 minutes.
Transfer onions to a plate and set aside.
Wipe the skillet clean.
In a small saucepan, combine beef broth, Worcestershire sauce, soy sauce, minced garlic, and thyme.
Bring mixture to a gentle simmer for 5 minutes.
Season with salt and pepper.
Strain through a small strainer and keep warm.
Arrange 4 bread slices on a work surface.
Layer each with 1 slice Swiss cheese, a generous portion of roast beef, caramelized onions, and a second slice of Swiss cheese.
Cover each with remaining bread slices.
Spread unsalted butter evenly on the outsides of each sandwich.
Heat a clean skillet or griddle over medium heat.
Grill sandwiches for 3 to 4 minutes per side, pressing gently, until bread is crisp and golden and cheese is melted.
Slice sandwiches in half and serve immediately with warm au jus for dipping.

My go-to tricks for the best results

Use room temperature roast beef so it warms through quickly without overcooking the bread. I like to fold the slices for extra heft and texture.
Caramelize the onions low and slow; stirring every couple minutes encourages even browning and a sweet, jammy finish. For inspiration on other crunchy-and-cheesy combos, check out my favorite twist on an apple grilled cheese at cheddar and apple grilled cheese.
Keep the au jus warm: serve it in a small teapot or warmed ramekin, so dipping doesn’t cool the sandwich.
Press gently when grilling to encourage a fast, even toast; too much pressure squeezes out the fillings.

Small changes that give you big variations

Swap Swiss for provolone or a smoked gouda to introduce smokiness.
Make it a giant open-faced melt with an extra layer of cheese and broil for two minutes until bubbling.
Turn it into a slow-cooker feast by making the roast beef and broth all day, then assembling—if you’re curious about that method, see this slow-cooker take: crockpot French dip sandwiches.
Add horseradish or Dijon to the beef for a bright kick, or include sautéed mushrooms for earthiness.

How to present and savor each sandwich

Serve the sandwiches halved, the cut edge revealing strings of melted cheese and layered roast beef. Pour a little au jus into a shallow ramekin so each dunk coats the edge of the bread, leaving a glossy sheen and an extra hit of savory richness. A crisp pickle or a small salad of peppery arugula dressed with lemon helps cut the richness and refresh the palate. If you want handheld-friendly options for a party, try pairing with light roll-ups inspired by quick comfort foods like delicious French dip tortilla roll-ups.

Keeping leftovers and reheating them right

Refrigeration: Wrap sandwiches tightly in foil or place in an airtight container; they’ll keep 2 to 3 days.
Freezing: You can freeze assembled (uncooked) sandwiches for up to one month. Thaw in the refrigerator before grilling.
Reheating: Re-toast in a skillet over medium-low heat with a lid on to help the cheese melt without burning the bread. You can also reheat in a toaster oven at 350 F until warm. Rewarm au jus gently on the stovetop and avoid boiling to keep the flavors balanced.

Curious minds want to know

Q: Can I use a different type of bread?
A: Absolutely. A sturdy sourdough or pane di casa works well, but avoid bread that’s too soft or it will get soggy when dipped.

Q: Is there a vegetarian version?
A: Swap roast beef for sliced seitan or thick-portobello steaks and use a vegetable broth-based dip with soy and Worcestershire (use vegetarian Worcestershire if needed).

Q: How do I make au jus richer without overpowering the sandwich?
A: Reduce the beef broth slightly to concentrate flavor and add a splash of balsamic or a teaspoon of butter at the end for silkiness.

Q: Can I prep elements ahead?
A: Yes—caramelized onions and au jus both keep well refrigerated for 2 to 3 days, making assembly quick.

Conclusion

This French Dip Grilled Cheese is one of those joyful crossovers that turns a simple grilled sandwich into a theatrical, comforting meal you’ll crave. If you want to explore other takes on this cozy classic, I like this quicker version from French Dip Grilled Cheese Sandwich – 30 Minutes Meals for weeknight inspiration, while a slightly different approach with handy tips appears at French Dip Grilled Cheese – Delish. For a smoky, grilled variation that’s great for outdoor cooking, check out Grilled French Dip – Over The Fire Cooking. Give it a try this week—I guarantee the first dunk into that shimmering au jus will make you smile.