Have leftover pork roast and need a tip on how to use it up? Make a delicious grilled pork tenderloin sandwich with mozzarella and caramelized onions!
Ever have leftover pork roast or pork tenderloin and wonder what you can do to use it up creatively? Recently I had leftover pork from dinner, so I made a Grilled Pork Tenderloin Sandwich with Mozzarella and Caramelized Onions for lunch! It tasted wonderful!
I enjoy having leftovers in the fridge, unlike my little sister Joni, who hates having them around. My personal theory is it’s awesome when you can cook once, then take some of the leftovers and “morph” them into a completely different meal. That was how this sandwich came into existence.
I was looking for something in our refrigerator for lunch, but didn’t want to have leftover pork… unless I could transform it into something else!
So… I put my thinking cap on and came up with the idea for this pork tenderloin sandwich! Here’s how to make it:
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Caramelize The Onions
Cook the sliced onions slowly in a skillet with a bit of olive oil for several minutes. Continue to cook until the onions have browned and caramelized.
“Build” The Pork Tenderloin Sandwich
Melt the butter in a large skillet on medium-low heat. Butter one side of a large piece of sourdough bread and place it butter side DOWN in skillet.
Generously layer the bread with thin slices of leftover cooked pork tenderloin. If necessary, lightly season the pork slices with salt and pepper.
Arrange the caramelized onions on top of the pork slices.
Spread a thin layer of sliced mozzarella (or grated) on top of the onions.
Butter one side of the other pieces of sourdough bread, and place them on top of the sandwich, butter side UP.
Time To Cook The Grilled Pork Tenderloin Sandwich
Cook the sandwich on medium-low heat until the bottom side of the bread has lightly browned.
Carefully turn sandwich over and cook the other side (like a grilled cheese sandwich). See how nice and golden brown the sourdough bread is now?
Continue cooking slowly until cheese has melted. You want the grilled pork tenderloin sandwich to be heated all the way through (low and slow!).
When the sandwich is done cooking, remove it from the skillet. Transfer it to a plate, and get ready to enjoy this sandwich!
It’s Time To Eat The Grilled Pork Tenderloin Sandwich!
Carefully cut the grilled sandwich in half… and enjoy! The tender pork slices, crunchy buttery sourdough bread, gooey melted mozzarella cheese and slight sweetness of the caramelized onions really make this sandwich special.
An entire grilled pork tenderloin sandwich is very filling! A half of this sandwich was all I could eat! If you don’t want to eat a whole sandwich, you can get 4 servings when you make two sandwiches.
Hope you will consider creating a delicious pork tenderloin sandwich when you have leftover pork roast or tenderloin! The sandwich was very good!
Looking For More SANDWICH Recipes?
You can find all of my sandwich recipes in the Recipe Index, located at the top of the page. A few of them include:
- Spicy Fish Sandwich with Chili Mayo
- Italian Meatball Sandwiches
- Mediterranean Chicken Sandwich
- Grilled “Thai” PB &J Sandwich
- Quick and Easy Open-Faced Tuna Melts
Interested In More Recipes?
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Have leftover pork roast and need a tip on how to use it up? Make a delicious grilled pork tenderloin sandwich with mozzarella and caramelized onions!
- 4 slices sourdough bread
- 1 Tablespoon butter (for skillet)
- 2 Tablespons enough butter to spread on bread (for grilling)
- 8 thin slices precooked pork tenderloin (enough to cover each sandwich)
- 1/2 onion , thinly sliced
- 1 Tablespoon olive oil
- thin slices mozzarella cheese (enough to cover sandwich)
- Heat olive oil in skillet on medium heat. Add sliced onions; cook slowly, stirring occasionally, for several minutes, until they have browned and caramelized.
- Melt butter in a skillet on medium-low heat. For each sandwich, butter one side of bread and place it butter side DOWN in skillet.
Cover bread with thin slices of leftover cooked pork tenderloin. Lightly season pork with salt and pepper. Divide and spread caramelized onions on top of pork. Spread a thin layer of sliced mozzarella (or grated) on top of onions. Butter one side of remaining pieces of sourdough bread, and place on top of the sandwich, butter side UP.
Cook on medium-low until bottom side has lightly browned.Carefully turn sandwich over. Continue cooking slowly until cheese has melted and sandwich is heated through (low and slow!). When sandwiches are done cooking, remove from skillet. Slice sandwich in half... and enjoy!
Here’s one more to pin on your Pinterest boards!
This recipe was great! I did add some Dijon mustard for a little extra flavor! Followed the recipe otherwise! Delish!
Glad you enjoyed it, Anna! Have a great day.
This was delicious. I have trouble making caramelized onions so I just grilled them. Before toasting bread, I heated my pork loin. Served with baby gerkin pickles. Was plenty for the two of us. Thanks for posting!
Glad you enjoyed this sandwich, Annie! Thanks for your note. Have a great day.
Great taste. I used Rye bread and Gruyere cheese. Half sandwich was perfect.
Ooh… rye bread and gruyere sound fantastic! Great combo… thanks for writing, Tina! Have a great day.
I had half of a pork tenderloin leftover and was looking for a new recipe to use it. Made this for dinner tonight. It was delicious. Thanks for the recipe.
Good morning, Jessica! So glad you enjoyed the sandwich (and the leftovers!). Take care, and have a great day.
We 💓 this sandwich. I used rye bread and it was fantastic!!! Hubby said he has had lots of specialty sandwiches in his working years and this topped ’em all!!!
Hi, Sharon… glad the sandwich was enjoyed. I LOVE the idea of using rye bread… yum. Gonna have to try that! Sorry for my late response. Been PLOWED with comments, and am slowly working through them all.
Wonderful sandwich! I removed my sautéed onions added more butter to the pan and threw in my thinly sliced leftover pork tenderloin to warm it a bit. Always hated leftover pork tenderloin…..
Good morning, Kimme, and thank you for writing! I am so glad you enjoyed the sandwich. I am right there with ya on the leftover pork tenderloin thing… ha ha! Take care, and have a good day.
Excellent, easily prepared dish.
Good morning, Rex! Thank you for taking time to write a note about this sandwich! You are right… it is a good sandwich and is easily prepared. Have a GREAT weekend.
that sounds so freakin delicious! I have everything except the sourdough bread but I’m gonna find a substitute lol. I never know what to do with leftover pork and it’s hard to reheat without ruining it.
Hey, Marie… thanks for taking time to write a quick note! Hope you enjoy the sandwich! You are completely right… it is definitely hard to reheat pork without “ruining” it. Have a GREAT day!
Very good recipe, I’m gonna make one right now, but substitute the mozzarella with smoked Gruyere. Nice and simple.
Ooh… smoked Gruyere would taste FANTASTIC on this sandwich! Thank for writing, and thanks for the suggestion, Cleveland! Have a great day!