A Meatloaf Burger With Mushroom Relish made from grilled meatloaf and topped with homemade mushroom relish. Quick and easy to make, this is a great way to use leftover meatloaf.

This is one of our favorite ways to use leftover meatloaf. The mushroom relish is a great topping for the meatloaf and it adds a unique flavor that complements the meatloaf.
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Ingredients to Make Meatloaf Burger With Mushroom Relish
To make this recipe, there are two parts, the burger and the relish.
Meatloaf burger ingredients:
- Leftover meatloaf. Cut the meatloaf into thick slices about 1 inch thick. We use our Smoked Meatloaf.
- BBQ sauce. Use your favorite BBQ sauce to brush on the meatloaf after grilling.
- Cheese. Slices of melty cheese work great for these burgers. Some of our favorites are gouda, havarti, and provolone.
- Burger buns.
Mushroom Relish ingredients:
- Mushrooms. We like to use cremini mushrooms.
- White onion.
- Garlic.
- Balsamic vinegar.
- Extra-Virgin Olive oil.
- Butter.
- Fresh thyme.
- Fresh rosemary.
- Salt and pepper.
Making Mushroom Relish
The best way to cook this relish is in a heavy-bottomed pot or cast iron pan. We use a cast iron Dutch oven because it holds the heat best.
Mushroom relish can be cooked outside on a side burner of a BBQ or over charcoal. This is how we cook it so that it is cooked alongside the meatloaf on the grill.
Grilling the Meatloaf for Meatloaf Burger With Mushroom Relish
When it comes to grilling the slices of meatloaf for this recipe, our go-to way is using our Blackstone griddle. This gives us the room we need to not only grill the meatloaf but also toast the buns on the other side of the griddle.
We have also grilled the meatloaf on the gas grill using grill mats. You can grill it without the mats but sometimes the meatloaf may break on the grill and fall into the BBQ, so we prefer using the grill mats.
How Else Can Mushroom Relish Be Used?
This relish is easy to make and it adds a ton of flavors to meatloaf burgers.
Leftover mushroom relish can be stored in an air-tight container in the fridge and reheated to use on steaks or pork chops.
Use this relish as a stuffing for chicken breasts or pork loins before cooking.
Meatloaf Burger With Mushroom Relish
Ingredients
Mushroom Relish
- 2 Tbsp butter
- 2 Tbsp extra-virgin olive oil
- ½ cup diced white onion
- 1 garlic bulb, minced
- 12 ounces mushrooms, cleaned and stemmed, sliced
- ¼ cup balsamic vinegar
- 2 sprigs fresh thyme
- 1 sprigs fresh rosemary
Meatloaf Burgers
- 4 slices of leftover meatloaf
- ½ cup BBQ sauce
- 4 cheese slices
- 4 hamburger buns
Instructions
Mushroom relish
- In a heavy-bottomed pot, melt the butter with the olive oil over medium heat.
- Add the onion and garlic and cook for 1 minute to soften.
- Add mushrooms and cook until mushrooms are softened and cooked through, stirring, about 3 or 4 minutes.
- Pour in the balsamic vinegar and herbs, stir, and cook for 3-4 minutes.
Meatloaf Burgers
- Heat griddle to medium-high heat.
- Grill the meatloaf for 2-3 minutes per side or until heated through.
- Brush the cut sides of the meatloaf with BBQ sauce.
- Add a cheese slice on each meatloaf piece.
- Toast the buns on the griddle until golden.
- Place a slice of meatloaf on the bottom part of each bun. Top with mushroom relish and top of bun.
- Serve immediately.



This was just what I was looking for! Had some meatloaf leftover and needed something the kids would eat. They loved it. Mostly picked off the mushrooms but my wife and I loved the mushroom relish.
Our kids love these as well. And when they were younger they ate them without the mushroom relish.