Caramelized Mushrooms and Onions are a perfect side dish to go along with a delicious grilled steak dinner. Try this recipe for mushrooms and onions for a flavorful twist with everyday ingredients.
Mushrooms can really enhance a meal. Two of my favorites recipes are my Air Fryer Portobello Mushrooms and my Stuffed Boursin Mushrooms.
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Why this Sautéed Mushroom and Onions Recipe is a Keeper
This easy side dish for steak is as delicious as it is simple to make. It’s super versatile and is packed full of deep, rich flavor.
- Versatility: This side dish can be used as a side or a topping for many different meals, from steak to burgers and beyond.
- Deep Flavor: The “low and slow” cooking method creates a rich, savory, and complex flavor that is deeply satisfying.
- Simple Ingredients: It transforms common, affordable ingredients into something special and delicious.
How Do I Clean Mushrooms for this Side Dish?
To clean mushrooms, wipe the mushrooms with a damp paper towel to remove the dirt, and dry them well with a paper towel.
Pro Tip for Sauteed Mushrooms and Onions
It’s important to slice the mushroom and onions at the same thickness. Use a mandolin to help you!
Ingredient Notes for Caramelized Mushrooms and Onions
This savory mushroom recipe uses easy, fresh ingredients that pack a punch of flavor.
Get the full printable recipe with specific measurements and directions in the recipe card below.
- Whole Mushrooms: A container of fresh white mushrooms.
- Onions: You will need 2 pounds of white onions or red onions to make easy sautéed mushrooms and onions for steak.
- All Purpose Seasoning: I like to keep All Purpose Seasoning in stock because it’s better than seasoning with just salt and pepper.
Variations and Substitutions
Easily customize this great recipe by experimenting. Take it to the next level by using different ingredients and trying different flavors.
- Spice: Add a pinch of cayenne pepper or red pepper flakes for a subtle kick.
- Tang: Deglaze the pan with a splash of balsamic vinegar, Worcestershire sauce or red wine at the end of cooking mushrooms and onions together.
- Herbs: Stir in fresh thyme or rosemary for an earthy flavor. Feel free to add some minced garlic.
- Mushrooms: You can use several mushrooms in this recipe. Cremini, white button, and shiitake mushrooms are all great choices for sautéing with onions. Cremini add a rich, meaty flavor, white buttons are mild and soak up seasoning well, and shiitakes bring a deeper, earthy taste.
How to Make Sauteed Mushrooms and Onions
In just 1 step, you can sauté mushrooms and onions. Serve on top or on the side of other dishes. This recipe takes patience, but the results are well worth it.
Get the full printable recipe with specific measurements and directions in the recipe card below.
- Caramelize the Veggies: In a large skillet over medium low heat, melt the butter. Add the onions and add the mushrooms with the All Purpose Seasoning. Cook until sliced onions and sliced mushrooms are golden brown.
Prep Ahead Suggestions to Make Caramelized Vegetables
Since this recipe is already super easy, there are only a couple things you can do ahead of time. But here is how you can get ahead for Thanksgiving and Christmas dinner.
- Slice Vegetables: Clean mushrooms and sweet onions ahead of time so that they are ready to go.
- Make Seasoning Blend: Be sure to make your seasoning blend ahead of time so it’s as easy as adding a little bit to the onions and mushrooms and cook.
Alternate Cooking Methods for Caramelized Onions and Mushrooms
Make this simple recipe another way by using your oven or instant pot if your stovetop is occupied with something else.
- Oven Roasting: Toss all ingredients on a baking sheet. Roast at a low temperature (300-350°F or 150-175°C) for 1-2 hours, stirring occasionally.
- Pressure Cooker: For a quicker method, you can use a pressure cooker to soften the ingredients. Then sauté on medium heat or medium high heat to brown.
Store, Reheat and Use Leftovers for Steak
- Store: Keep in an airtight container in the refrigerator for up to 4 days, or freeze in ice cube trays for long-term storage.
- Reheat: Reheat in a skillet with a splash of water or broth to prevent drying out.
- Use Leftovers: Use as a topping for burgers, steaks, or sandwiches; mix into omelets, frittatas, or rice bowls; or as a base for French onion soup.
Questions and Reader Interactions for this Recipe
It’s best to cook the mushrooms and onions low and slow, so it can take 30 minutes or longer.
Start with onions. They take longer to soften and caramelize. Add mushrooms once the onions are golden and fragrant.
Overcrowding the pan traps steam. Cook in batches and use medium-high heat to help them brown instead of steam.
Tips for Making Sauteed Onions and Mushrooms
- Patience is Key: True caramelization happens over low, slow heat. Don’t rush it!
- Deglaze the Pan: Periodically add a splash of water or white wine to scrape up the flavorful brown bits from the bottom of the pan.
- Cut Uniformly: Slice the onions and mushrooms into even pieces so they cook at the same rate.
- Serve this recipe with: Serve with Pork Chops with Mushroom Gravy or Caramelized Onion Burger.
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Flavorful Caramelized Mushrooms and Onions
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Ingredients
- 3 Tablespoons Butter
- 2 pounds White onions, peeled and sliced thin
- 8 ounces Sliced mushrooms
- ½ teaspoon All Purpose Seasoning Blend
Instructions
- Melt butter in a large skillet over medium-low heat.
- Add onions, mushroom and All Purpose Seasoning to the skillet and toss to combine.
- Cook over medium-low heat for 30 minutes, stirring occasionally.
- When onions and mushrooms are golden, remove from heat and serve immediately.
Christina’s Notes
- Instant Pot: You can also make this recipe using an instant pot for quicker results. First cook the mushroom and onions on the pressure cook setting for 5 minutes. Then drain excess liquid and sauté for an additional 3-5 minutes.
- Quicker Prep Time: To reduce prep time, you can get pre-sliced mushrooms and onions or cut up ahead of time and store in the fridge.
- Wine: Red Wine or White Wine adds to your favorite dishes.
- Fresh Herbs: Fresh Parsley, thyme, black pepper or whatever you need.
- Scale the recipe: Simply adjust the serving size in the recipe card and the ingredients will update automatically.
- Make your own All Purpose Seasoning: When a recipe calls for All Purpose Seasoning, you can use my homemade All Purpose Seasoning recipe or substitute salt and pepper to taste.
- Meat doneness: I always use a meat thermometer to test for doneness when cooking meat.
- Use unsalted butter: I use unsalted butter so I can control the salt level in the recipe.
- Preheat the oven: Unless otherwise noted, always preheat your oven before baking.
For more helpful information about this recipe, such as variations, substitutions and other pro-tips, check out the blog post.
Caramelized mushrooms and onions, how could it any think but yummy! Cannot wait to experiment how versatile it is.
I don’t understand in your recipe you use a frying pan. But then below you refer to baking them. You don’t provide instructions for baking. Please advise how to making using the baking method. I can’t wait to make this.
Thank you,
Karen Burns
Spread the onions in an even layer on a large rimmed baking sheet or in a large Dutch oven. For a true “caramelization” (browning and sweetening), avoid overcrowding the pan too much, as this can lead to steaming. If doing a very large batch, use a Dutch oven with a lid initially, or multiple baking sheets.
Low and Slow: This is key. Oven caramelization typically happens at a lower temperature (e.g., 300-350°F or 150-175°C) for a longer period.
Stir Occasionally: Stir the onions every 15-30 minutes. This ensures even cooking and prevents burning. As they cook, they’ll release moisture, then start to brown and become sweet. The total time can be 1-3 hours, depending on the quantity and desired level of caramelization.