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A bowl of caramelized onions and mushrooms on a cutting board with a cast iron skillet of mushrooms in the back.
5 from 1 vote

Caramelized Onions and Mushroom Recipe

A richly savory, restaurant-worthy side made from slowly caramelized onions and mushrooms. This mostly hands-off recipe delivers deep umami flavor and pairs beautifully with steak, burgers, or roasted chicken.
Print Recipe
Prep Time:10 minutes
Cook Time:35 minutes
Total Time:45 minutes

Ingredients

  • 8 ounces sliced mushrooms
  • 1 sliced onion
  • 2 tablespoons butter
  • 2 tablespoons avocado oil
  • ½ teaspoon salt
  • ½ teaspoon pepper
  • ½ teaspoons garlic powder
  • ¼ teaspoon cayenne pepper
  • 3 cloves of fermented garlic minced

Instructions

  • Heat a cast iron or stainless steel skillet for 10 minutes on medium heat
  • Add 2 tablespoons butter, 2 tablespoons avocado oil, and 1 sliced onion and stir
  • Cook for 5 minutes to allow the onions a head start in caramelizing and softening
  • Add 8 ounces sliced mushrooms, ½ teaspoon salt, ½ teaspoon pepper, ½ teaspoons garlic powder, and ¼ teaspoon cayenne pepper and stir
  • Allow the mushrooms to cook for 10 minutes. During this time, the water in the mushrooms will release. Allow it to cook off before the next step.
  • Add 3 cloves of fermented garlic and stir. Continue to cook on medium heat for 5 more minutes, stirring occasionally to prevent burning.
  • Turn the temperature to medium low (between 2 and 3 on my stove) and allow to slowly caramelize until softened and brown around the edges of the mushrooms. This process takes around 20 minutes
  • Stir and check to see if the mushrooms need to cook any further. They should be tender, brown, and slightly crisped around the edges

Notes

Don’t worry about the water absorption that happens when you wash your mushrooms. I’ve seen recommendations to only wipe the dirt off to avoid water, but I don’t do that. I prefer to wash the dirt off. The water from the mushrooms will seep out. You do want to cook the water off to ensure browning. Simply, let the mushrooms cook at medium high until the water has released, then evaporated. At this point adding soy or fish sauce will allow it to absorb into the mushrooms.
Try to let the onions and mushrooms cook without disturbing them. The Maillard reaction works best when the heat is continual. 

Nutrition

Calories: 141kcal | Carbohydrates: 6g | Protein: 2g | Fat: 13g | Saturated Fat: 4g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 6g | Trans Fat: 0.2g | Cholesterol: 15mg | Sodium: 340mg | Potassium: 242mg | Fiber: 1g | Sugar: 2g | Vitamin A: 229IU | Vitamin C: 4mg | Calcium: 16mg | Iron: 0.4mg
Course: Side Dish
Cuisine: American
Keyword: Caramelized Onions and Mushrooms
Servings: 4 people
Calories: 141kcal