3/4 cup finely chopped shallots, divided
2 tablespoons minced garlic, divided
2 tablespoons extra-virgin olive oil, divided $
2 tablespoons red wine vinegar
1 tablespoon Dijon mustard
1 tablespoon Worcestershire sauce
1 teaspoon hot sauce (such as Tabasco)
1/2 teaspoon dried thyme
1 1/2 pounds top round steak, trimmed $
2 (8-ounce) packages presliced mushrooms $
3/4 teaspoon kosher salt, divided
1/2 teaspoon freshly ground black pepper, divided
1 1/2 cups unsalted beef stock (such as Swanson), divided
1 tablespoon all-purpose flour $
1 1/2 tablespoons butter $
2 teaspoons lower-sodium soy sauce

3/4 cup finely chopped shallots, divided 2 tablespoons minced garlic, divided 2 tablespoons extra-virgin olive oil, divided $ 2 tablespoons red wine vinegar 1 tablespoon Dijon mustard 1 tablespoon Worcestershire sauce 1 teaspoon hot sauce (such as Tabasco) 1/2 teaspoon dried thyme 1 1/2 pounds top round steak, trimmed $ 2 (8-ounce) packages presliced mushrooms $ 3/4 teaspoon kosher salt, divided 1/2 teaspoon freshly ground black pepper, divided 1 1/2 cups unsalted beef stock (such as Swanson), divided 1 tablespoon all-purpose flour $ 1 1/2 tablespoons butter $ 2 teaspoons lower-sodium soy sauce

1. Combine 1/2 cup shallots, 1 tablespoon garlic, 1 table­­spoon oil, vinegar, mustard, Worcestershire, hot sauce, and thyme in a large bowl, stirring with a whisk. Add beef, turning to coat. Refrigerate 3 1/2 hours, turning occasionally. Let beef mixture stand at room temperature 30 minutes before cooking.
2. Preheat broiler to high. Place oven rack 4 inches from broiler.
3. Heat a large nonstick skillet over medium-high heat. Add remaining 1 tablespoon oil to pan; swirl to coat. Add remaining 1/4 cup shallots, remaining 1 tablespoon garlic, and mushrooms to pan; cook 10 minutes or until mushrooms are browned, stirring occasionally. Stir in 1/4 teaspoon salt and 1/4 teaspoon pepper. Combine 1/4 cup stock and flour in a small bowl, stirring with a whisk. Add flour mixture and remaining 1 1/4 cups stock to pan; simmer 4 minutes or until slightly thickened. Remove pan from heat; stir in butter and soy sauce. Keep warm.
4. Remove beef from marinade; discard marinade. Wipe any marinade from beef with a paper towel. Sprinkle beef with remaining 1/2 teaspoon salt and remaining 1/4 teaspoon pepper. Place a wire rack on a jelly-roll pan. Add beef to rack. Broil 5 minutes on each side for medium-rare or until desired degree of doneness. Place beef on a cutting board; let stand 5 minutes. Cut across the grain into thin slices. Serve with mushroom mixture.