01 - Melt butter in a large skillet over medium heat. Add chopped shallot and cook for 2 minutes until translucent.
02 - Stir in minced garlic and cook for 30 seconds until fragrant.
03 - Add sliced mushrooms and cook, stirring occasionally, until browned and softened, approximately 6 to 8 minutes.
04 - Pour in white wine and cook for 2 to 3 minutes, scraping the pan to release any browned bits, until the wine is reduced by half.
05 - Add stock, sea salt, black pepper, and thyme. Simmer for 5 minutes to slightly reduce the liquid.
06 - Stir in heavy cream and crème fraîche if using. Simmer gently for 3 to 4 minutes until the sauce thickens.
07 - Remove from heat, stir in chopped parsley, and adjust seasoning to taste.
08 - Serve the sauce hot over desired main dishes, garnished with additional fresh parsley.