Melt 1 1/2 teaspoons butter in a nonstick skillet over medium heat. Add shallots and mushrooms; sauté for 4 minutes. Add 1 cup wine and 3/4 cup consommé; cook for 5 minutes, stirring frequently. Remove the mushrooms with a slotted spoon; place in a bowl. Increase heat to high; cook wine mixture until reduced to 1/2 cup (about 5 minutes). Add to mushrooms in bowl; set aside. Wipe pan with a paper towel.
Sprinkle pepper over steaks. Melt 1 1/2 teaspoons butter in pan over medium heat. Add steaks; cook 3 minutes on each side. Reduce heat to medium-low; cook 1 1/2 minutes on each side or until desired degree of doneness. Place on a platter; keep warm.
Combine soy sauce and cornstarch. Add 1/2 cup wine and remaining consommé to skillet; scrape skillet to loosen browned bits. Bring to a boil; cook 1 minute. Add mushroom mixture, cornstarch mixture, and dried thyme; bring to a boil, and cook 1 minute, stirring constantly. Serve sauce with steaks. Garnish with thyme sprigs, if desired.