Caramelized Onions and Mushrooms is a simple side dish that is low carb and gluten free. Pair it with chicken or steak, or enjoy it as a light meal on its own. Fast, easy, and delicious.
I'm always looking for fast and easy side dish options to fuel the family. What I love about this easy recipe is that it's full of flavor, with minimal work and effort. The caramelization of the onions brings out a sweetness to them that pairs perfectly with the cooked mushrooms. Who knew that these two ingredients were literally the perfect pairing?
The good news is that the caramelization process isn't hard to do at all - and this is why I make it so often. You can literally use this as pizza toppings or use it to compliment any type of main entree.
I've made this to pair with chicken, pork chops, and even a burger or two! It's not only flavorful, but it's an affordable way to add veggies to your daily diet.
Onions - You can use any type of onions that you like. Yellow onions and white onions are great, but sweet onions work, too. Change it up every time to change up the flavor.
Mushrooms - Mushrooms can be changed as well. I love using white button mushrooms, but the flavor of baby Bella mushrooms really stands out as well.
Olive oil - This is used for cooking up the mushrooms and onions in the skillet.
Salted butter - Adds flavor and richness.
Salt and pepper - To taste. You can add as much or as little as you want in the final step.
How to Make Caramelized Onions and Mushrooms
Be sure to clean mushrooms and gather up the list of ingredients to get started.
Step One: Heat butter and oil in a large skillet or frying pan over medium heat.
Step Two: Add the onions, reduce to medium-low, and cook, stirring occasionally until they are light golden brown.
Expert Tip: The trick to perfectly caramelized onions is to be patient. If you turn up the heat they can scorch and burn. Caramelizing them well takes about 45-50 minutes.
Step Three: Add the mushrooms. Cook until they are browned and tender.
Step Four: Season with salt and pepper. Serve immediately.
Add fresh herbs - You can add fresh herbs like garlic, black pepper, fresh parsley, kosher salt, thyme, lemon pepper, and more.
Drizzle with balsamic vinegar - Want a pop of flavor? Add this and see what you think!
Try thicker slices - You may like your onions and mushrooms to be a tad bit thicker in texture, so change up the thickness each time that you make this dish.
Sauce - Stir in a soft cheese in the final step like cream cheese, Boursin, brie (remove the rind), or mascarpone for an amazing caramelize onion and mushroom sauce. If it is too thick add a splash of cream.
Cheese - Garnish with some freshly shredded parmesan cheese for added flavor.
Why do you carmelize onions on low heat?
Cooking it at this temp helps the caramelization process to happen at a slow and steady rate. Anything hotter like medium or medium high heat can burn the onions.
This is also why it's important to use the oil and butter so that it replaces the moisture with ingredients that will brown them. You'll know that you're at the end of cooking when the mushrooms are smaller than when they started, and the onions are translucent.
How do you store leftover mushrooms and onions?
Any leftovers need to be stored in the fridge. Make sure that you let them cool down all the way before adding them to an airtight container.
You can also add leftovers to the freezer for later, too. The same process applies to letting them cool down all the way and then adding them to a freezer-safe bag or container.
To reheat, you can heat them up in the microwave until they're warm or thawed all the way through.
Can I shorten the cooking time?
You can, but you may lose out on that caramelized flavor and texture that you're looking for. The longer that they cook, the more that will cook down and be nice and tender and soaking up the flavors.
If you remove the ingredients too early and decide that you want to cook them down even more, no worries. Just add the mixture back to the skillet and cook them for a bit longer to get them to be the consistency that you want.
Can you mix in other ingredients?
Yes, you can. You can add in other sliced veggies. You can caramelize the veggies right along with the mushrooms and onions or add different types of veggies at the end to have a soft and crunchy texture, too.
If you want to add some meat into the mixture, ground beef or ground turkey/ground chicken would work as well. Just make sure that you brown and cook the meat all the way through before adding.
What to serve caramelized onions and mushrooms with?
In our photos, we served this with a smoked t bone steak. It was amazing.
You can also serve it with grilled chicken for another dinner option. Or in an omelet for breakfast!
Caramelized Onions and Mushrooms
- 3 onions thinly sliced
- 2 lb mushrooms sliced
- 2 tablespoon olive oil
- 2 tablespoon salted butter
- 1 teaspoon salt
- ¼ teaspoon pepper
- Heat butter and oil in a large skillet over medium heat.
- Add the onions, reduce to medium-low, and cook, stirring occasionally until they are light golden brown. This takes about 45-50 minutes.
- Add the mushrooms. Cook until they are browned and tender.
- Season with salt and pepper. Serve immediately.