Wipe mushrooms with a damp paper towel or use a soft brush to remove dirt. Trim the stem ends if dry. Slice larger mushrooms into 1/4-inch (6 mm) slices; leave small ones halved or whole for even cooking.

Mince the garlic and finely chop the shallot. Strip thyme leaves from stems and chop parsley. Measure out wine/broth and cream if using.

Cooking

Heat pan and add fat

Place a large skillet over medium-high heat. Add the butter and olive oil. Heat until the butter is melted and starts to foam but is not browned (about 1 minute). The oil raises the smoke point and prevents butter from burning.

Sear mushrooms

Add the mushrooms in a single layer (do not overcrowd — cook in batches if necessary). Let them cook undisturbed for 2–3 minutes so they brown on one side. Stir and continue to cook, stirring every 1–2 minutes, until mushrooms are golden brown and most of their moisture has evaporated, about 6–8 minutes total.

Add aromatics

Reduce heat to medium. Add the chopped shallot and minced garlic to the pan. Cook, stirring, until fragrant and softened, about 1–2 minutes, taking care not to burn the garlic.

Deglaze

Pour in the white wine or vegetable broth to deglaze the pan, using a wooden spoon to scrape up any brown bits from the bottom. Let the liquid cook down by half, about 2 minutes. This concentrates flavor and lifts fond from the pan.

Finish with cream and herbs

If using, stir in the heavy cream and let simmer for 1–2 minutes until slightly thickened and coating the mushrooms. Stir in the thyme, salt, and pepper. Taste and adjust seasoning.

Finishing

Remove the pan from heat. Stir in the chopped parsley and lemon juice if using, to brighten the dish. Serve immediately as a side, over toasted bread, pasta, or as a topping for steak or polenta.

If you cooked in batches, combine all mushrooms back into the pan after finishing the final batch and toss briefly to warm through before serving.