In medium iron skillet, melt half the butter in half the oil until hot.
Add mushrooms and saute quickly, about 5 minutes.
Remove with slotted spoon.
Add remaining butter and oil over "high" heat.
Pat filets dry.
Brown filets well, about 4 minutes per side for medium rare.
Cook to desired doneness.
Remove from skillet to a platter and keep warm.
Pour nearly all fat from skillet and add beef broth.
Boil over "high" heat, scraping the pan.
Cook until reduced to 2 tbsp then add wine, thyme, salt & pepper.
Add mushrooms and heat through.
Serve mushroom sauce on top of steak.
Fried Sweet Potato Shoestrings: Run 2-3 large sweet potatoes through a food processor with the blade set to julienne.
Rinse well to remove the extra starch and pat dry with paper towels.
Fry the sweet potatoes in very hot vegetable oil just a few seconds until golden.
Drain on brown paper and sprinkle lightly with salt.
Ready in 1 hour.