Preheat the oven to 425°F (220°C). Clean mushrooms by wiping with a damp cloth or quickly rinsing and patting dry. Trim stems if needed and halve or quarter mushrooms so pieces are roughly uniform in size (about 3/4–1 inch).

Oil and season

In a large bowl toss the mushrooms with 2 tablespoons olive oil, 1 tablespoon butter (melted), 3/4 teaspoon kosher salt, and 1/2 teaspoon freshly ground black pepper until evenly coated.

Roast

Spread mushrooms in a single layer on a rimmed baking sheet. Roast on the middle rack for 18–22 minutes, stirring or shaking the pan once halfway through, until mushrooms are deeply browned at the edges and have released their juices. If pan juices are excessive, drain off 1–2 tablespoons.

Add garlic and thyme

When mushrooms have about 3 minutes left in the oven, sprinkle minced garlic and thyme over them and return to the oven. This gently cooks the garlic so it’s fragrant but not bitter.

Creamy Sauce

Sauté shallot

While mushrooms roast, heat a 10-inch skillet over medium heat and add 1 tablespoon butter. When melted, add the finely minced shallot and a pinch (about 1/4 tsp) of salt. Cook, stirring, until softened and translucent, about 3–4 minutes.

Deglaze

Increase heat to medium-high and pour in 1 dl (approximately 3.5 fl oz / 100 ml) dry white wine or broth. Scrape up any browned bits from the pan and simmer until liquid is reduced by about half, about 2–3 minutes.

Add cream and cheeses

Reduce heat to medium-low and stir in 3 tablespoons heavy cream, 2 tablespoons cream cheese (if using) and 2 tablespoons grated Parmesan. Whisk until smooth and slightly thickened, about 2–3 minutes. If the sauce becomes too thick, add 1–2 tablespoons water or broth to reach desired consistency.

Season and finish

Stir in 1 teaspoon lemon juice, 1/4 teaspoon kosher salt (adjust to taste), 1/4 teaspoon freshly ground black pepper, and 2 tablespoons chopped parsley. Taste and adjust seasoning. If you want a touch of heat, sprinkle in 1/4 teaspoon red pepper flakes.

Combine with mushrooms

Add the roasted mushrooms (and any reserved pan juices) into the skillet with the sauce. Toss gently over low heat for 1–2 minutes so mushrooms are evenly coated and warmed through. Sprinkle an extra tablespoon of Parmesan if desired and remove from heat.

To Finish (optional)

Serve the creamy roasted mushrooms immediately over toasted bread slices, pasta, polenta, or as a side. Garnish with additional chopped parsley and grated Parmesan. Adjust salt and lemon if needed.