Spinach & Mushrooms Recipe

Prepare vegetables

Clean the mushrooms by wiping them with a damp paper towel or a soft brush; trim stems if needed and slice about 1/4 inch thick. Rinse spinach only if very dirty and spin or pat dry thoroughly; large leaves can be roughly chopped. Peel and thinly slice the onion. Mince the garlic and set all prepared vegetables aside.

Sauté onion and mushrooms

Heat a large skillet over medium-high heat. Add 1 tablespoon olive oil and the butter. When the butter foams and oil shimmers, add the sliced onion and a pinch of salt; cook, stirring occasionally, until the onion is soft and beginning to brown, about 5–7 minutes. Add the sliced mushrooms in a single layer as much as fits; avoid overcrowding (cook in batches if needed). Let mushrooms cook undisturbed 3–4 minutes to develop color, then stir and continue cooking until they release their liquid and it evaporates, about another 4 minutes.

Add garlic

Reduce heat to medium. Push the mushrooms and onions to the side and add the remaining 1 tablespoon olive oil to the clear space. Add the minced garlic and cook 30–45 seconds until fragrant, stirring to combine with the mushrooms and onions so garlic doesn't burn.

Add the spinach to the pan in batches, adding handfuls and letting them wilt slightly before adding more so the pan doesn't overflow. Stir frequently to incorporate spinach with mushrooms and onion. Once all spinach is wilted and incorporated (about 2–4 minutes), season with the measured 1 teaspoon salt, 1 teaspoon freshly ground black pepper, and 1/4 teaspoon red pepper flakes if using. Cook another 1–2 minutes so flavors meld and excess moisture evaporates.

Remove the pan from heat. Stir in 1 tablespoon fresh lemon juice to brighten the flavors. If using, sprinkle 2 tablespoons grated Parmesan over the mixture and toss to combine. Taste and adjust seasoning with additional salt, pepper, or lemon as desired.

Serve warm as a side dish, or use as a topping for toast, pasta, grain bowls, or omelets. Leftovers keep in an airtight container in the refrigerator for up to 3 days; reheat gently in a skillet or microwave.