Gather all ingredients before starting the recipe.
Slice 1/2 lb mushrooms, thinly slice stems, if using.
Melt 3 tbsp unsalted butter add 1/2 tbsp vegetable oil to a medium sized sauce pan over medium heat.
Sauté mushrooms until they start to brown. Season with kosher salt and freshly ground black pepper.
Add 2 tbsp shallots, finely chopped and stir to combine, cook 1 to 2 minutes.
Add 1/2 cup white wine and simmer until reduced by half.
Add 1/2 cup Sauce Espagnole2 tbsp tomato sauce and 1 tsp chopped parsley.
Bring to a boil over medium heat, stir and remove from heat, reserve until ready to use.
