Buttery Sautéed Mushrooms and Onions
Ingredients
- 1 lb (454 g) cremini mushrooms, wiped clean and sliced 1/4 inch thick
- 2 medium yellow onions (about 400 g), halved and thinly sliced
- 1 tbsp (15 ml) olive oil
- 2 tbsp (28 g) unsalted butter
- 1 tsp fresh thyme leaves
- 3/4 tsp kosher salt, divided
- 1/4 tsp black pepper
- 1 tsp (5 ml) balsamic vinegar
Instructions
- Slice the mushrooms and onions. Keep the mushroom slices fairly even so they brown at the same pace.
- Heat a wide skillet over medium heat. Add the olive oil and onions with 1/4 tsp salt. Cook for 10 to 12 minutes, stirring every minute or two, until soft and golden at the edges.
- Raise the heat to medium-high. Push the onions to the edge of the pan and add the mushrooms in an even layer. Leave them undisturbed for 3 minutes so the cut sides can brown.
- Toss the mushrooms with the onions. Cook 6 to 8 minutes more, until the released liquid has cooked away and the mushrooms have browned edges.
- Lower the heat to medium. Add the butter, thyme, remaining salt, and pepper. Toss for 1 minute until the butter coats everything.
- Add the balsamic vinegar and toss for 30 seconds. Serve when the onions are soft and golden and the pan is glossy, not watery.
Small fixes that matter
- Use the widest skillet available; crowding delays browning.
- Do not add the butter until the mushroom liquid has mostly cooked away.
- For deeper onion color, keep the heat at medium and add 5 to 10 minutes before adding the mushrooms.
Good with
steak, burgers, polenta, toast with ricotta, mashed potatoes.
Storage and reheating
- Refrigerate cooled leftovers in an airtight container for up to 3 days.
- Reheat in a skillet over medium heat until hot; add a splash of water only if the pan looks dry.
- Freeze only if texture is secondary; thawed mushrooms and onions are best folded into sauces or soups.