This Easy Caramelized Mushrooms and Onion recipe is a delicious side or condiment to a variety of dishes. And we have a foolproof method for caramelizing onions and mushrooms that is as easy as it is consistent!
Rich, sweet and incredibly savory, these caramelized mushrooms and onions are perfect toppers for veggie or black bean burgers, grain bowls, seared steak or chicken, crusty bread and even crispy fried fish. But don't stop there! This recipe can also serve as the base for a cream sauce, a hearty vegetable soup or a fluffy rice pilaf.
Caramelized vs. Sautéed
The key difference between caramelized and sautéed mushrooms and onions is the doneness of the vegetables. Saluted onions and mushrooms will be just starting to turn golden brown and but still have a bit of tenderness. Flavor wise, when sautéed onions and mushrooms taste slightly toasty and slightly sweet. But when caramelized, the flavors take on a whole new level of complexity! They turn incredibly sweet yet savory and they are cooked so long they practically melt in your mouth.
While making caramelized mushrooms and onions takes a bit longer than simply sautéing the vegetables, we have a method we stand by, one that is so consistent it's hard for us to caramelize any other way.
Ingredients That Matter
A handful of simple ingredients is all you need for this recipe:
- Mushrooms. While you can use just about any mushroom for this recipe, we like the consistency of cremini (baby bella) mushrooms. In a pinch, you can certainly use white button mushrooms. The most important thing is the mushrooms are both fresh and clean. How to tell if your mushrooms are fresh? Simply, they should smell like the dirt or mushrooms; they should NOT smell fishy. That's a sure sign the mushrooms are old or there was too much moisture in their packaging. What's the best way to clean mushrooms? You can use a small brush, toothbrush or even a paint brush to clean the dirt from the mushrooms, but the easiest option is a slightly damp paper towel. Simply use the towel to rub off any dirt. Be sure to clean around the gills of the mushrooms.
- Onion. For this recipe we like to use a sweet onion, but you can certainly use yellow onions. One large (about 1 lb.) Vidalia or other sweet onion works well. Simply peel the onion and cut into thin slices.
- Olive Oil & Butter. We use two fats in this recipe, one for cooking and one for flavor. Use standard olive oil (or another neutral high heat oil) to cook the onions and mushrooms. And finish the dish with a pad of butter, letting the butter melt into the caramelized onions and mushrooms right at the end of the cooking process.
- Thyme. A bit of fresh thyme right at the end compliments the sweet and rich onions and mushrooms very well. You can skip it in a pinch, but it won't be quite as tasty without it!
How to make Caramelized Mushrooms and Onions
Our favorite method for caramelizing onions is to cook the onions over medium heat covered for about 15 minutes. The key is keep the onions covered as they cook. How it works: As the onions cook, the liquid evaporates and condenses on the inside of the lid. That moisture eventually falls back into the pan, providing just enough moisture on the bottom of the pan to keep it from scorching. That means you can, essentially, let the onions caramelize for 15 minutes and only stir once or twice!
Add 2 tablespoons of the oil to the bottom of a large heavy-bottom skillet or cast iron skillet. Add the onions then turn the heat to medium-high. Once the pan is hot, stir once, cover and reduce heat to medium.
Cook the onions about 15 minutes, stirring once or twice and adjusting the heat down to medium-low if it starts to scorch. At this point the onions should be dark golden brown. You could cook them another 5-10 minutes, covered again, and you'll have caramelized onions! But, now we are going to add the mushrooms.
Move the onions to the edge of the skillet then add the remaining 1 tablespoon oil to the middle of the skillet. Add mushrooms in a single layer. You'll be adding the full 1 pound of mushrooms in 3-4 batches. Once the mushrooms are in a single layer, don't touch them! Let them sear until golden brown, about 3 minutes. Then stir the onions and mushrooms together and move the mixture around the edge of the skillet. Repeat this process of adding more mushrooms, searing them, then stirring them into the onions, with the remaining mushrooms.
When the last mushrooms are seared off, remove the skillet from the heat and add the thyme and butter and stir until the butter melts into the onions and mushrooms. At this point the mushrooms should be golden brown and slightly juicy inside and the onions should be dark brown, toasty and very sweet.
How to Serve Caramelized Mushrooms and Onions
These caramelized mushrooms and onions are perfect as a burger topping, spooned onto grain bowls or as the base of a savory creamy steak sauce. When cooked long enough, the natural sugars in the onions turn exceptionally sweet and complex, making it ideal for a wide range of recipes. And the caramelized mushrooms take on a savory, umami packed flavor. That mixture of the onions' sweetness and the mushrooms' umami make this such a special recipe.
Here are some other serving suggestions:
- Add a spoonful on top of our Easy Cherry Tomato Soup recipe
- Make a batch of our Pulled Chicken in a Dutch Oven then add these caramelized mushrooms and onions and serve with some rice or in a tortilla wrap
- Try serving as a side to our Smothered Skillet Chicken with Artichokes and Red Peppers
- Stir the onions and mushrooms into our Spaghetti Arrabiata for a spicy, sweet and savory pasta dish
Did you know you can freeze caramelized mushrooms and onions? Cool to room temperature then store in a freezer-safe zip-top bag for up to 3 months.
If you want to make a double batch of this recipe, we recommend removing the onions from the skillet before caramelizing the mushrooms or the onions will overcook.
Recipe
Easy Caramelized Mushrooms and Onions
- Total Time: 35 min.
- Yield: 2 ½ cups 1x
Description
This Easy Caramelized Mushrooms and Onion recipe is a delicious side or condiment to a variety of dishes. And we have a foolproof method for caramelizing onions and mushrooms that is as easy as it is consistent!
Ingredients
- 1 large (about 1 lb.) sweet onion, thinly sliced (about 5 cups)
- 3 Tbsp. olive oil, divided
- 1 lb. cremini mushrooms, cleaned and sliced (about 6 cups)
- ½ tsp. table salt
- 1 Tbsp. unsalted butter
- 1 ½ tsp. fresh thyme leaves
Instructions
- Add sliced onions and 2 tablespoons of the oil to a large heavy-bottom skillet or cast iron skillet. Heat skillet over medium-high. Once hot, stir onions and sprinkle with salt, cover and reduce heat to medium. Cook until the onions are golden brown, about 15 minutes, stirring a couple times through the cooking process and adjusting heat down to medium-low if the pan starts to scorch.
- Remove cover and move onions to the sides of the skillet. Add remaining 1 tablespoon oil to the center of the skillet and add a handful of the mushrooms in a single layer to the center of the skillet. Cook, undisturbed, until seared, about 3 minutes. Stir mushrooms into onions then move the mixture to the edges and sear more mushrooms in a single layer. Repeat this process with remaining mushrooms.
- Remove skillet from heat and add butter and thyme and stir until butter melts into vegetables. Serve hot or cool to room temperature and store in an airtight container in the refrigerator for up to 3 days.
Notes
- You can also use white button mushrooms.
- Can't find sweet onions? Try using 1 pound of yellow onions.
- Want to add more flavor? Add a minced garlic clove at the end of the cooking process, or add a splash of Worcestershire sauce or soy sauce.
- You may freeze leftovers in a freezer-safe zip-top bag for up to 3 months.
- Prep Time: 5 min.
- Cook Time: 30 min.
- Category: Sides
- Method: caramelizing
- Cuisine: American
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