In small skillet, melt 2 tbsp/30 mL of the butter over medium heat; fry shallots, garlic and half of the salt until shallots are softened, about 2 minutes. Add mushrooms and sauté until tender, about 4 minutes. Remove from heat; set aside.

With mallet or bottom of heavy pan, flatten steaks to about 1/2-inch/1 cm thickness.

In separate skillet, heat oil over high heat; add remaining butter. As soon as butter melts, add steaks and sear each side until lightly browned; sprinkle all over with pepper and remaining salt. Reduce heat to medium-high; cook until desired doneness, about 1 minute longer for rare or 2 to 3 minutes for medium-rare. Transfer each steak to a warmed plate and keep warm.

Pour off fat from skillet. Reduce heat to medium and stir Madeira into skillet; stir in mushroom mixture and any juices. Boil until liquid is reduced to about 1 tbsp/15 mL. Spoon over steaks.

Makes 2 servings.