Sautéed Onions And Mushrooms Recipe

Prepare vegetables

Peel the onions, halve them lengthwise, then slice thinly (about 1/8-inch / 3 mm). Wipe mushrooms with a damp towel or quickly rinse and dry; trim stems if needed and slice mushrooms into 1/4-inch (6 mm) slices.

Heat pan

Place a large skillet or sauté pan over medium-high heat. Add the olive oil and 1 tablespoon of the butter. Allow the fat to shimmer but not smoke (about 1 minute).

Start sautéing onions

Add the sliced onions to the hot pan in an even layer. Sprinkle with 1 teaspoon salt. Cook, stirring every 1–2 minutes, until onions have softened and started to become translucent and lightly golden, about 6–8 minutes.

Add mushrooms

Push onions to the side or make a single layer and add the sliced mushrooms in a single layer if possible. Sprinkle mushrooms with 1/2 teaspoon salt to encourage moisture release. Let mushrooms cook undisturbed 2–3 minutes to brown on one side, then stir to combine with onions. Continue cooking until mushrooms are browned and most of their moisture has evaporated, about 6–8 more minutes.

Reduce heat to medium. Add the remaining 1 tablespoon butter and the minced garlic (press or finely chop). Stir immediately and cook 30–45 seconds until fragrant but not browned.

Add the fresh thyme leaves and the remaining 1/2 teaspoon salt plus the 1/2 teaspoon black pepper (see note on adjusting). Stir to combine and let the flavors meld for 30–60 seconds.

Deglaze the pan by pouring in the white wine or stock (2 tablespoons). Use a wooden spoon to scrape up any browned bits from the bottom of the pan. Cook 1–2 minutes until the liquid has mostly evaporated and the mixture is glossy.

Turn off the heat. Stir in the chopped parsley and optional lemon juice to brighten the flavors. Taste and adjust seasoning with additional salt and pepper if needed.

Serve warm as a side, topping for steak or burgers, mixed into pasta, or cooled for sandwiches. Leftovers keep in an airtight container in the refrigerator for up to 4 days.