Best Mushrooms and Onions Sauce: Simple & Flavorful – An American Classic Revealed!

Oh, Katz’s Delicatessen, you sneaky sensory seducer! In the battle between my taste buds and you, my palate waves the white flag. I mean, if a pilgrimage to Katz’s could change my sauce game in ways I had never anticipated, who am I to resist? Not all heroes wear capes—and not all revelations happen in the classic “aha!” moments. Honestly, that sandwich practically demanded the creation of a fabulous new recipe.

So today, I give you the not-so-secret sauce that has infiltrated my culinary radar: Mushrooms and Onions Sauce. A wholesome blessing that nestles like a warm hug on the taste buds, while simultaneously making you say, “Oh heavens, what’s in this heavenly potion?” And guess what? It’s no Hogwarts sorcery—it’s a humble, loving revolution of the sauce world!

Unveiling this recipe will prove to be a game changer in every sense of the word. Your entire definition of what a sauce can do for your meals is about to be rewritten! Trust me when I say you’ll use this nifty little gem to zhuzh up your dishes more often than not. Dive into this mushroom-y, onion-y adventure (no scuba gear needed), and give your taste buds their well-deserved vacay. Once you’ve tried it, there’s no going back!


  1. Butter, unsalted – For a creamy and rich taste in the sauce.

  2. White mushrooms – Adding an earthy flavor to the dish.

  3. Sweet yellow onion – A must-have for its balance of sweetness and slight pungency.

  4. Salt and pepper – Basic staples that enhance the flavor and bring out the best in the mushrooms and onions.

  5. Worcestershire sauce – A magic ingredient that adds depth of flavor.


  1. Looking for a quick and easy way to add some flavor to your meal? Look no further than this delicious mushrooms and onions sauce!
  2. To start, you’ll need a skillet, spatula or wooden spoon, 3 tablespoons unsalted butter, 1 pound of mushrooms (I prefer white, but shiitake or baby Portobello work great too), 1 sweet yellow onion, ½ teaspoon of salt and pepper, and 2 tablespoons of Worcestershire sauce.
  3. First, melt the butter over medium-high heat in the skillet. Once it’s nice and hot, add in your sliced mushrooms and cook for about 5 minutes, or until they start to brown.
  4. Next, reduce the heat to medium and add in your sliced onion, salt, pepper, and Worcestershire sauce. Cook everything together for another 5-7 minutes, or until the mushrooms and onions are browned and soft. If you notice that the mushrooms and onions are starting to soak up too much of the moisture in the pan, add in a little more Worcestershire sauce one teaspoon at a time to keep things from drying out.
  5. And that’s it! The perfect way to add some delicious flavor to your meal without spending hours in the kitchen. Just remember, a sweet yellow onion is a must in this recipe. White or red onion will change the taste completely.

Serving Suggestions for Mushrooms and Onions Sauce

Here are a few serving options to get you started with this flavorful sauce!

  • Slather it on your favorite sandwich, like a classic grilled cheese or a veggie panini.
  • Use it as a topping for your next pizza night, especially if you’re a fan of mushroom and onion toppings!
  • Add it as a filling for an omelette or frittata for a tasty breakfast dish.
  • Serve it as a side dish with your favorite grilled or roasted meats, like chicken, steak or fish.
  • Use it as a base for a creamy mushroom soup. Add some milk or cream and blend until smooth.
  • Serve it as a dipping sauce for vegetables, crackers, or bread.

Did you know that the sweetness in an onion comes from the natural sugar content? So, make sure to use a sweet yellow onion for this recipe to get the best results!


Can I use a different type of mushroom in this recipe?

Of course! I recommend white mushrooms, but you can also use shiitake mushrooms or baby Portobello mushrooms. Just make sure they’re sliced to relatively the same size!

Can I use a different type of onion in this recipe?

I wouldn’t recommend it. A sweet yellow onion is the perfect onion for this dish – white or red onion will change the flavor completely.

What do I do if the mushrooms and onions soak up too much of the moisture in the pan?

No problemo! If the mushrooms and onions soak up too much of the moisture in the pan, just add additional Worcestershire sauce 1 teaspoon at a time to avoid them drying out.

Is this recipe vegan-friendly?

Unfortunately, this recipe calls for unsalted butter, which is not vegan-friendly. If you’re looking for a vegan alternative, you can use plant-based butter instead.

How many servings does this recipe make?

This recipe makes 6 servings.

The Ultimate Mushrooms and Onions Sauce

This recipe is a perfect balance of flavors, with tender mushrooms and sweet onions in a rich and savory sauce.
Prep Time 5 minutes
Cook Time 10 minutes
Total Time 15 minutes
Course Sauce
Cuisine American
Servings 6 portions
Calories 191 kcal


  • Skillet
  • Spatula or wooden spoon
  • Cutting board
  • Knife


  • 3 tablespoons unsalted butter
  • 1 pound white mushrooms, sliced
  • 1 large sweet yellow onion, sliced
  • 1 teaspoon sea salt
  • 1 teaspoon freshly ground black pepper
  • 2 tablespoons Worcestershire sauce
  • 2 cloves garlic, minced
  • 1 teaspoon thyme leaves
  • 1 teaspoon dried rosemary
  • 2 tablespoons dry white wine
  • 2 tablespoons heavy cream
  • Fresh parsley, chopped (optional)


  • Melt the butter in a large skillet over medium-high heat.
  • Add the sliced mushrooms and cook for 5 minutes, until they start to release their moisture and brown slightly.
  • Reduce the heat to medium, add the sliced onions, salt, pepper, Worcestershire sauce, garlic, thyme, and rosemary. Cook for another 5-7 minutes, until the onions are soft and translucent.
  • Deglaze the pan with the white wine, scraping any browned bits from the bottom of the pan. Cook for 1-2 minutes, until the wine has reduced by half.
  • Stir in the heavy cream and cook for another 2-3 minutes, until the sauce has thickened slightly.
  • Serve hot, garnished with chopped parsley, if desired.


If the mushrooms and onions soak up too much of the moisture in the pan, add additional Worcestershire sauce 1 teaspoon at a time to avoid them drying out.
For a vegetarian version, use a vegetarian Worcestershire sauce or soy sauce.
For a gluten-free version, make sure the Worcestershire sauce is gluten-free.


Calories: 191kcalCarbohydrates: 10gProtein: 4gFat: 17gSaturated Fat: 10gCholesterol: 47mgSodium: 592mgPotassium: 524mgFiber: 2gSugar: 5gVitamin A: 553IUVitamin C: 5mgCalcium: 35mgIron: 1mg
Keyword Vegetarian, Gluten-free
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