This grilled cheese sandwich comes at you with a lot of promise. Stay with me on this one, you won’t be disappointed. Picture it, juicy delicious comfort of a warm pot roast, caramelized-herbed onions, melted gooey cheese stuffed between two crusty, perfectly toasted pieces of buttery bread.

There are a lot of parts to this cozy-cool-weather inspired sandwich, but I guarantee it’s worth it and they are super simple for any weeknight dinner.

Rustic Pot Roast French Onion Grilled Cheese Sandwich

The Pot Roast

You can use leftovers from this traditional pot roast – which is what inspired this recipe. If you’re out of leftovers but you’re craving this delicious grilled cheese, don’t worry I included a pot roast recipe below, just start it during your morning coffee break while you work from home and voilà – there you have it!

Caramelized-Herb Onions

These caramelized-herb onions are buttery sweet with bold fall flavors that come from fresh sage leaves and rosemary sprigs, adding another layer of to this rustic grilled cheese sandwich.

The key to perfectly caramelized onions is to allow the onions develop flavor as they slowly brown and soften, only stirring occasionally to prevent burning (about 5 minutes).

This all comes together in a snap which makes this perfect for a busy weeknight dinner. Serve it with a side salad or a bowl of your favorite soup.

Rustic Pot Roast French Onion Grilled Cheese Sandwich

Juicy warm pot roast, caramelized-herbed onions, melted gooey cheese stuffed between two crusty, perfectly toasted pieces of buttery bread.

4.75 from 4 votes

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Prep Time: 20

Cook Time: 30

Crock Pot (Pot Roast)(not active time): 6

Total Time: 6 50

Servings: Sandwiches

Ingredients

Crock pot French Onion Pot Roast

2 lbs Beef – Chuck
2 medium Onions sliced
2 cups Beef Stock
2 tsp Garlic Salt
1 tsp Black Pepper
1 packet Lipton Onion Soup

Rustic Rot Roast French Onion Grilled Cheese Sandwich

4 tbsp Butter divided
2 medium Onions thinly sliced
¼ tsp Salt
1 cup Leftover Pot Roast juice or Beef Stock (optional)
2 sprigs Fresh Rosemary
7-8 Fresh Sage Leaves
8 oz Gruyère Cheese shredded
8 slices Swiss Cheese
8 slices Crusty Bread Sourdough or any type that is your favorite

Instructions

If you are making the French Onion Pot Roast – add all the ingredients into a crockpot, set it to high for 5-6 hours, let it remain on the warm setting until you're ready to make the grilled cheese sandwiches.
Shred the beef. Set the onions aside – you can use them in the caramelized onions if you want to.
Make the caramelized onions. In a pan, over medium heat, add 2 tbsp of butter, your sliced onions, herb and ¼ tsp of salt.
Allow them to slowly brown as they soften.
Only stir occasionally to prevent burning (about 5 minutes).
Optional – To add even more robust flavors, if you have them, add in your French Onion Pot Roast Onions and your reserved Pot Roast juice (or beef stock). Slowly reduce the juice over medium heat (about 2-3 minutes).
To make the sandwiches:
In a pan, over medium heat, melt 2 tbsps of butter, rub 4 slices (one side) of bread in the melted butter and set aside. They will be your "tops" to the grilled cheese sandwich.
Then in the pan, add the bottom slice of bread. I did two at a time, but if you can fit all four then do them all at the same time. Add two slices of Swiss cheese to each sandwich, pile on shredded pot roast, caramelized onions and top with a generous sprinkle of shredded Gruyère cheese.
As the cheeses start to melt, place on the top slice – melted butter side up. Once the bottom of the sandwich becomes perfectly "grilled" brown, very carefully and slowly so that the filling doesn't fall out, flip your sandwiches to allow the other side to brown. Once the bread is perfectly brown and the cheeses are melted, remove and serve immediately.