The Best Thing to Happen to Leftover Pot Roast
These patty melts turn last night’s pot roast into crispy, melty magic. With caramelized onions, two kinds of cheese, and a creamy sauce that pulls it all together, they’re everything you want in a hot sandwich—no one will even guess it started as leftovers.
Here’s why you’ll love it:
- Perfect use for leftover pot roast
- That dreamy sauce—just mayo and steak sauce, but it makes the sandwich
- Crispy on the outside, gooey on the inside
- Totally customizable with whatever cheese or bread you’ve got
- Comfort food vibes in under 30 minutes
Believe me when I say that this sandwich is the epitome of diner-style comfort food. I highly recommend some French fries or a bowl of Creamy Tomato Parmesan Soup.
Leftover Pot Roast Patty Melts
Ingredients
For the sandwiches:
- 2-3 cups leftover shredded pot roast
- 8 slices sturdy bread
- 3 tablespoons butter plus more for the bread
- 2 medium onions thinly sliced
- Salt and pepper to taste
- 4 slices Provolone cheese
- 4 slices cheddar cheese
For the sauce:
- 1/2 cup mayonnaise
- 3 tablespoons steak sauce
- 1/8 teaspoon pepper
Instructions
- Re-heat the pot roast in the microwave. Butter one side of all 8 slices of bread.
- Melt 3 tablespoons of butter in a large skillet. Add onions and cook over medium heat, stirring frequently, until onions are soft and golden brown.
- Season with salt and pepper and remove from heat.
- Combine the sauce ingredients in a medium bowl.
- Heat a griddle over medium-high heat. Spread a layer of the sauce on the unbuttered side of 4 slices of bread. Top with a piece of cheddar cheese.
- Top each slice of cheddar with about 1/2 cup of pot roast, a generous portion of onions, and the slice of Provolone cheese. Top with the remaining slice of bread, buttered side out.
- Grill, flipping once, until both sides are browned and crispy.
- Serve patty melts with the remaining sauce, for dipping.
Nutrition
Here’s how to make sure your patty melts turn out perfectly:
Recipe Tips
- Butter matters: Spread it evenly to get a golden crust all the way to the edges.
- Don’t rush the onions: They’re the soul of the sandwich—deep flavor comes from slow cooking.
- Don’t overload: Too much filling makes flipping messy. Keep it hearty, but balanced.
- Use a press or skillet weight if you want an extra crispy finish (and more diner-style vibes).
Leftovers, Again?
These sandwiches are best hot off the griddle, but here’s how to make them work for later:
- Prep ahead: Caramelize onions and mix the sauce in advance. Store separately in the fridge.
- Reheat gently: Leftovers can be crisped back up in a pan over low heat or in a toaster oven. Avoid microwaving—it’ll soften the bread.
Switch Things Up
A few easy variations can give this sandwich a new spin every time:
- Try a different sauce: BBQ mayo, garlic aioli, or even horseradish cream.
- Go veggie-friendly: Swap in roasted mushrooms or sautéed peppers.
- Change the bread: Texas toast, rye, or even focaccia would be delicious.
The grilled onions are the star of these sandwiches, as far as I’m concerned. Sure, it takes a little bit of time and attention to get them caramelized just right. But it’s SO worth it!
Be sure to save this recipe to your favorite Pinterest board for later.
20 comments
margie
These were perfect! We used a sturdy bread, but could only eat half a sandwich each. Means I have lunch for next week! Thanks for such a creative and delicious recipe. Easy too!
Elizabeth Bull
What is a good bread?
Sharon
I have the same question. What is “sturdy” bread?
Danelle
Like a crusty sourdough type bread. Not just regular sandwich bread.
Monica Booth
This recipe was a hit! It seriously tasted like something I’d order in a higher-end pub-style restaurant. I accidentally crisped the onions up a bit in the frying pan but they ended up adding a nice hint of crunch. I could put that sauce on a flip flop and eat it happily. I’d never thought to mix mayo and bbq sauce together! If I do anything different next time, it’ll be to get a bigger loaf of bread lol. So good I’m making it again for lunch tomorrow!