You will need 2 separate skillets for this recipe. 1) In a large skillet over medium high heat, saute the mushrooms and onions in 3 tbsp. of melted butter until the mushrooms are tender. Season to your taste with salt and pepper and stir in the flour. Pour the heavy cream into the mixture and mix well. Set aside in a warm place. 2) In a second skillet , melt the remaining 2 tbsp butter and bring to a high heat. Season the steaks with salt and pepper and fry for 2 1/2 to 3 minutes per side for rare and increase the cooking time by 1/2 minute per side for each additional degree of doneness you like. Remove the steaks from the pan and arrange them on a platter or individually. Add the scotch to the pan drippings and bring to a boil for 1 to 2 minutes, mix into the mushroom sauce. Pour over the steaks and serve immediately. Serve extra sauce in a bowl for passing.