Step 1: Heat the Oil and Sauté the Mushrooms

Start by heating olive oil or butter in a large skillet over medium-high heat. Once the oil is shimmering, add the sliced mushrooms in a single layer. Avoid stirring them too frequently—letting them sit for a minute or two helps develop a deep golden-brown caramelization. After about 4-5 minutes, stir occasionally to ensure even cooking.

Step 2: Add the Garlic and Seasonings

Once the mushrooms are golden and have released their moisture, add the minced garlic to the skillet. Stir continuously for about 30 seconds to 1 minute, ensuring the garlic doesn’t burn. Then, season with salt, black pepper, and red pepper flakes (if using).

Step 3: Add the Spinach and Finish the Dish

Reduce the heat to low and add the fresh spinach to the skillet. It will look like a lot at first, but spinach wilts quickly. Gently toss everything together, allowing the spinach to cook down for about 2-3 minutes until just wilted.

For an extra layer of flavor, drizzle balsamic vinegar and soy sauce over the mixture and stir well. This step enhances the natural umami flavors of the mushrooms while adding a slight tang.

Step 4: Garnish and Serve

Remove the skillet from heat and transfer the sautéed mushrooms and spinach to a serving dish. If desired, sprinkle with grated Parmesan cheese for a final touch of richness. Serve immediately as a side dish, topping, or light meal.