Few things beat the deep, rich aroma of mushrooms and onions sizzling in a hot pan. This classic combination delivers bold umami, a kiss of sweetness, and a hint of garlic that complements everything from steaks and burgers to pasta and grains. Whether you’re cooking for a weeknight dinner or jazzing up a holiday spread, sautéed mushrooms and onions are always a flavorful win.

What makes this dish so magical is its simplicity. With just a handful of ingredients and a few smart techniques, you can elevate humble vegetables into something savory and irresistible. Plus, it’s versatile enough to serve as a side, topping, or even folded into eggs for breakfast.

Preparation Phase & Tools to Use

To get perfectly caramelized, tender mushrooms and onions, your tools make a big difference. Here’s what you’ll need:

Heavy Skillet or Cast Iron Pan: This retains heat beautifully and ensures even browning. Non-stick pans work, but cast iron delivers that unbeatable sear.
Wooden Spoon or Silicone Spatula: Crucial for stirring and scraping up flavorful brown bits without damaging your pan.
Sharp Chef’s Knife: Precise cuts make a difference in how evenly your mushrooms and onions cook.

Cutting Board: Keep your prep safe and organized.
Mixing Bowl (optional): For tossing your mushrooms with oil or seasoning beforehand, if you like to pre-coat.

Proper tools help you control moisture, heat, and texture—the key to that golden, savory finish we crave.

Ingredients for the Sautéed Mushrooms and Onions

16 oz mushrooms (Baby Bella or White Button)
1 large yellow or sweet onion
2 tablespoons butter, divided

1 tablespoon olive oil
2 cloves garlic, minced
½ teaspoon salt

¼ teaspoon black pepper
1 tablespoon fresh parsley, chopped (optional)

How To Make the Sautéed Mushrooms and Onions

Step 1: Prep Your Ingredients

Clean mushrooms with a damp paper towel (don’t rinse under water), then slice evenly. Peel and slice the onion into strips or half-moons. Mince the garlic.

Step 2: Heat the Pan

Place your skillet over medium-high heat. Add olive oil and 1 tablespoon of butter. Let it melt and shimmer before adding anything in.

Step 3: Add the Onions

Toss in the sliced onions and stir occasionally. Cook for 5-7 minutes until they begin to soften and turn golden.

Step 4: Add the Mushrooms

Spread the mushrooms in a single layer. Don’t stir too much at first—you want them to brown. After 5 minutes, stir and continue cooking another 4-5 minutes.

Step 5: Season and Sizzle

Add minced garlic, salt, and pepper. Stir well. Cook for an additional 2 minutes to blend the flavors.

Step 6: Finish with Butter and Garnish

Add the remaining butter, toss to coat, and let everything get glossy and tender. Garnish with chopped parsley if desired.

How to Serve and Store Sautéed Mushrooms and Onions

These mushrooms and onions are incredibly versatile. Serve them hot over grilled steak, toss them into pasta, layer them on burgers or sandwiches, or add them to omelets and quesadillas.

To store leftovers, let them cool completely, then place in an airtight container in the fridge for up to 4 days. Reheat in a skillet over medium heat to bring back their savory richness. Avoid microwaving, as it can make them soggy.

Frequently Asked Questions

Can I use a different type of mushroom?

Absolutely! Cremini, portobello, shiitake, or a mix all work great. Just adjust the cook time depending on thickness.

Can I make this dairy-free?

Yes, you can substitute butter with vegan butter or just use more olive oil.

Can I freeze sautéed mushrooms and onions?

While you can freeze them, the texture may change slightly upon thawing. They’re best enjoyed fresh or refrigerated.

What if I don’t have fresh garlic?

You can use ¼ teaspoon of garlic powder in place of each clove.

Should I salt the mushrooms early or late?

Salting too early can draw out moisture and make them steam instead of brown. Add salt after they’ve started browning.

What dishes pair well with this?

Try pairing with grilled meats, mashed potatoes, rice bowls, frittatas, or even creamy polenta.

Want More Side Dish Ideas?

If you love these sautéed mushrooms and onions, you’ll probably enjoy these other favorites:

Balsamic Roasted Vegetables for a tangy oven-roasted side.

Creamy Garlic Mashed Potatoes to soak up all that savory flavor.
Honey Glazed Carrots if you’re craving something sweet and vibrant.
Cheesy Cauliflower Bake for a comfort food classic.

Garlic Green Beans that bring a crisp, fresh bite.

Find even more ideas on my Pinterest @LifeWithOlivia where I share new sides and kitchen hacks daily.

Save This Recipe for Later

📌 Save this recipe to your Pinterest board so you can come back to it any time.

And let me know in the comments how yours turned out. Did you caramelize the onions longer? Use a different mushroom blend? I love hearing how others make these recipes their own.

Questions are welcome too—let’s help each other cook better, together.

Sautéed Mushrooms and Onions

Author: Olivia McKenney

Total Time: 25 minutes
Yield: 4 servings
Diet: Vegetarian

Print Recipe

Description

This easy and flavorful sautéed mushrooms and onions recipe is the perfect companion for grilled meats, pasta dishes, or breakfast eggs. Rich with umami, kissed with sweetness, and spiked with garlic, it’s a versatile side you’ll make again and again.