Roast Beef Brie and Caramelized Onion Grilled Cheese Sandwich
When you’re craving something a little more special than an ordinary grilled cheese, take lunch or dinner to the next level with my Roast Beef Brie Caramelized Onion Grilled Cheese sandwich. Three ingredients come together between golden brown slices of artisan bread for a restaurant-worthy sandwich at home.
I really believe there is a trick to making the perfect grilled cheese sandwich. Besides using your favorite ingredients, you need a cheese that melts well, and Brie is a good choice. Medium heat is best. Too low and it takes forever. Too high and you burn the sandwich.
The latter is what my husband does. Also key: don’t leave the sandwich while it’s cooking, because that’s a surefire way to overcook it. No phone calls, don’t check your emails, make the sandwich. Using a great bread is essential too. Sure, you can use any old wheat or white bread, but switch that up to an artisan bread for a noticeably yummier sandwich.
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Why this roast beef brie caramelized onion grilled cheese recipe works
One bite of this gourmet sandwich and you’ll wonder where it’s been all of your life!
- The rich Brie cheese gets beautifully melty without becoming greasy.
- Uses simple ingredients with gourmet flavor.
- Crispy, buttered bread provides a great textural contrast to the creamy Brie cheese.
- Caramelized onions add a natural sweetness that balances the sandwich.
Ingredients for roast beef grilled cheese
All you need are five ingredients to make this roast beef brie caramelized onion grilled cheese sandwich. It’s restaurant-worthy.
- Artisan bread
- Roast Beef
- Onions
- Brie
- Butter
Tips and Suggestions
- Use either a grill pan or a large skillet to make these roast beef brie caramelized onion grilled cheese sandwiches.
- Learn how to caramelize onions perfectly for the best sandwich. Add a pinch of salt when you add the onions to the skillet.
- Butter your bread crust to crust. That means, butter every last inch of the side of the bread you will toast. Trust me on this, it gives the sandwich great texture.
- Slice the rind off of the Brie cheese while it’s cold. Allow the cheese to come to room temperature after slicing it for the sandwiches.
- I did not put anything on the inside of the bread. The creamy Brie and buttery bread are enough, but if you like you can add some Dijon mustard, garlic aioli, or horseradish sauce.
Assemble the sandwich
- Build the roast beef brie caramelized onion grilled cheese sandwich by adding slices of deli roast beef and caramelized onions on a slice of bread.
- Add the sliced Brie cheese.
- Top with the second slice of buttered bread.
- Serve!
All recipes are tested in my Florida kitchen exclusively by me.
Common mistakes when making a grilled cheese sandwich
My family calls me the expert grilled cheese maker. The only time someone else will make grilled cheese is when I’m sick. Even though I’ve tried to teach them, there are some common mistakes some make when making grilled cheese. Some things to watch out for include:
- The best roast beef brie caramelized onion grilled cheese is made over medium heat. Too high of heat and it will easily burn. You want a nice, golden color and crispy texture.
- Not caramelizing the onions long enough, or caramelizing them too long. You want them to have some crunch, so to speak. You don’t want them too brown.
- Using too much filling. If there’s too much roast beef or onions, the cheese won’t melt over it, causing the sandwich to come apart.
- Using cold cheese from the refrigerator. Room temperature cheese melts better.
Choosing the best bread for grilled cheese sandwiches
While you can certainly use any bread for a grilled cheese sandwich, an artisan bread such as sourdough or a round Italian loaf will result in the crispiest sandwich. I used white mountain bread, which is exclusive to our grocery store, Publix. It’s very similar to Italian.
Breads like potato or wheat that are very soft won’t give you the crispy aspect.
What can I serve with roast beef brie caramelized onion grilled cheese sandwiches?
A gourmet sandwich needs a gourmet side such as crispy onion strings, sweet potato chips, rosemary roasted potato peelings, or baked sweet potato fries.
Gourmet sides aren’t the only thing to serve with this roast beef brie caramelized onion grilled cheese. Complete the meal with broccoli cheddar soup or French onion soup.
When I make this sandwich for lunch, I serve iced tea, sometimes raspberry or strawberry, but if I serve it for dinner, I’ve been known to take the dining experience to the next level with a glass of wine, such as a pinot noir.
More Delicious Sandwiches
But if you’re looking for other sandwiches, try these family favorites: Hot Colby Ham Sandwiches, Roast Beef, Ham, and Bacon Club Sandwich, or Easy French Dip Sandwiches.
Do you have to remove the rind from the Brie?
While you don’t have to remove it completely, it’s best to remove most of it so the cheese will melt well into the roast beef and caramelized onions. The rind is edible.
How do you keep a grilled cheese crispy?
It’s difficult to keep a grilled cheese crispy unless you serve it right away. You can assemble the sandwiches but cook them on the griddle just before you want to serve them.
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Roast Beef, Brie and Caramelized Onion Grilled Cheese
Ingredients
- 4 slices of artisan bread I used Pane Tuscan
- Butter softened to room temperature
- 1 medium onion sliced
- 8 slices roast beef
- 1 8 ounce wheel Brie cheese, rind removed
Instructions
- In a medium skillet over medium heat cooked the sliced onions in a tablespoon of butter until caramelized. Set aside.
- Heat a clean skillet over medium heat.
- Butter one side of each piece of bread and set aside. Butter the entire side, edge to edge.
- Lay one slice of bread, butter side down, in preheated skillet. Top with cheese, caramelized onions, roast beef and more cheese. Top with bread slice, butter side up. Repeat with remaining ingredients. Turn when buttered side is golden and cheese is melting. Don’t fiddle with the heat. Remove when both sides are golden and cheese is melted.
- Slice sandwiches in half and serve.
Recipe Notes
Roast beef brie caramelized onion grilled cheese sandwich originally posted April 3, 2017, and updated with new photos and better information August 6, 2026.
This looks and sounds amazing! I am greatly looking forward to trying this recipe!
What a great idea to pair roast beef with brie. The caramelized onion sounds like an amazing addition to the sandwich. I love horseradish sauce with roast beef, so I’m going to try it that way! Thank you for sharing this recipe!
Oh lawdy…I could go for one of these right this very minute. Such a great use of flavors!
Now this is my kind of grilled cheese! Roast beef AND brie? Yes please!
Haha, I always fall victim to washing dishes while making a grilled cheese.. one side is usually a touch darker than desired, but not enough that no one will eat it! I just love that you put caramelized onions in your grilled cheese.
This sounds almost too good to be true! Some of my favorite flavors!
That sounds really yummy! I LOVE brie! Can’t wait to try this one 🙂
Roast beef makes amazing grilled cheese! I love the caramelized onions. So good.
I’d love this with a steaming bowl of soup!
I’m drooling so hard over here. This looks so delicious. I almost want to go home and make this today for lunch! Wish I had all the ingredients now!
Melted brie is always good, sounds like a tasty sandwich!
What a great sounding sandwich. YUM