01 - Place a large skillet over medium heat and melt the unsalted butter.
02 - Add the finely chopped shallot and sauté for 2 minutes until softened.
03 - Stir in the minced garlic and cook for 30 seconds, then add the sliced mushrooms.
04 - Increase heat to medium-high and cook, stirring occasionally, until mushrooms are golden and their liquid has evaporated, about 6 to 8 minutes.
05 - Pour in the stock and simmer for 2 minutes, scraping up browned bits from the skillet.
06 - Reduce heat to medium-low and stir in heavy cream, thyme, salt, and pepper.
07 - Simmer gently for 3 to 5 minutes, stirring occasionally, until desired sauce thickness is achieved.
08 - Stir in the chopped parsley, adjust seasoning as needed, and serve hot with optional parsley garnish.