6 slices brioche, toasted, crusts removed if preferred, each piece cut into 4 squares
Using a cloth or paper towel, clean mushrooms to remove the grit and dirt. Finely chop mushrooms and set aside.
In a large skillet over medium-high heat, melt 2 tablespoons butter. Saute shallots and thyme until soft, 3 minutes. Add the remaining butter and mushrooms and cook, stirring, 5 minutes. Add the wine, reduce heat to medium, cover and saute 5 minutes until the alcohol has evaporated.
While the mushrooms cook, in a small bowl, stir together the heavy cream, sour cream, salt, and pepper. When wine has mostly evaporated, stir the dairy mixture and the chives into the mushrooms until combined. Remove from heat. Spoon mushroom mixture on toasted bread. Sprinkle with chives if you like.