Name: Easy Caramelized Onions and Mushrooms
Prep time: 10 min
Cook time: 30 min
Total time: 40 min
Cuisine: American
Ingredients: 1 large onion, thinly sliced; 12-16 oz mushrooms (such as cremini or button), sliced; 2-4 tablespoons butter; Salt and pepper, to taste; 1/4 cup stock or water

Appetizers and Sides

Dec 8

Written By Merritt Allen

bowl of caramelized onions and mushrooms

Easy Caramelized Onions and Mushrooms

Caramelized onions and mushrooms are not only easy, tasty, but are the perfect side dish! This dish is a dynamic duo of onions and mushrooms and only requires a few ingredients to deliver maximum flavor! Caramelized onions and mushrooms are reduced slowly to make a savory sensation that goes with your favorite bread, noodles, meat, or potatoes! Caramelized onions and mushrooms are a delicious combination that adds depth and flavor to any dish. Whether you're preparing a savory side dish or enhancing the taste of your main course, these caramelized gems will take your cooking to the next level.

I love this recipe for how simple it is! It is a great side dish for the holidays, as a meal preparation side, and can be enjoyed during any time of the year! With so few ingredients but so much flavor, there is no reason not to make these! If you are looking for what to pair these onions and mushrooms with, check out my meal prep guide on the contact page or home page!

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Common Questions For Caramelized Onions and Mushrooms:

Do You Use Oil or Butter Caramelize Onions?

You can use either butter or oil to caramelize your onions and mushrooms. I love using butter, since its a little creamier and saltier than olive oil.
Salted butter is best for this recipe, the salt adds flavor and the butter milk solids cook with your onion and create a really creamy and sweet dish.

What is the Difference Between Caramelized Onions and Sautéed Onions?

Caramelized onions are a slow cooked version of onions that sweeten in the pan as their natural sugars cook. Sautéed onions are cooked much faster, usually over higher heat, to produce a more smoky flavor. Caramelized onions will be very soft in texture, while sautéed onions can maintain a certain bit when cooked. This is because higher heat will sear the outside of the onion but will not reduce and bring out the sugar of the onions the same.

Should You Cover Onions when Caramelizing?

You can cover onions when caramelizing to help them reduce faster. Covering the onions will produce more water, which you can evaporate off by leaving the lid off of the onions and mushrooms once they have reduced quite a bit.
I often cover the mushrooms when I first add them to the pan with the onions. Mushrooms are really bulky but reduce down A LOT, and covering them will help speed the process up.

What Goes With Caramelized Onions and Mushrooms?

Caramelized onions and mushrooms go with so many main dishes! You can enjoy them as a holiday side dish, heaped on top of bread, or paired with a good steak just to name a few ways I have enjoyed this dish.
If you are serving this dish as a holiday side dish, it is great with prime roast or dinner rolls. You can even serve alongside my Challah bread recipe, which is an easy bread to make for the holiday season!
Caramelized onions and mushrooms also go great with eggs! You make a delicious scrambled using caramelized onion and mushroom leftovers. Let me know how you like to serve your onions and mushrooms in the comments below!

What Kind Of Pan Goes With Caramelized Onions and Mushrooms?

You can use a non-stick or a stainless steel pan. Since you are reducing the onions and mushrooms, they will release water and should not stick to the bottom of the pan, especially since your are doing it slowly. If you find that your onions or mushrooms start to stick when caramelizing, you can add 1/4 cup of stock. This stock will reduce and will add to the sauciness of the mushrooms.

caramelized onions and mushrooms with sourdough

Ingredients For Easy Caramelized Onions and Mushrooms:

Recipe for Caramelized Onions and Mushrooms

1 large onion, thinly sliced
12-16 oz mushrooms (such as cremini or button), sliced
2-4 tablespoons butter
Salt and pepper, to taste
1/4 cup stock or water

Equipment Needed For Caramelized Onions and Mushrooms:

Skillet- this recipe is quite simple! You Just need to thinly slice your vegetables and slow cook them in a skillet!

Steps For Caramelized Onions and Mushrooms

Slice the Onions and Mushrooms
1. Thinly slice your onion into the thinnest slices possible. This will help produce that thin, stringy caramelized onion we all love!
2. Wash and remove the mushroom stems. Thinly slice the caps and set aside.
Caramelize the Onions and Mushrooms
1. Over medium to low heat, add 2 Tbs of butter. Once melted, add the Onions.
2. Stir to incorporate the butter
3. Let simmer for 8-10 minutes, stirring often.
4. Once the onions have reduced down and are transparent, add the mushrooms and a pinch of salt.
5. Cover with a lid and let reduce for a couple of minutes.
6. Remove the lid, and add more butter if the skillet is looking dry.
7. Continue to stir the onions and mushrooms until the mushrooms are reduce and onions are a light brown.
  1. This step can take between 15-20 minutes before your onions taste really sweet!
Serve with Salt and Pepper
1. When ready: serve with salt, pepper, and sourdough or alongside your favorite main dishes!