Ingredients •2 teaspoons butter, divided •1 cup vertically sliced yellow onion •1 cup vertically sliced red onion •1/4 cup sliced shallots •3 garlic cloves, minced •1/2 cup fat-free, lower-sodium beef broth •2 cups green beans, trimmed •2 tablespoons balsamic vinegar •1/4 teaspoon salt, divided •4 (4-ounce) beef tenderloin steaks •1/4 teaspoon freshly ground black pepper

Preparation
Melt 1 teaspoon butter in a medium saucepan over medium-high heat
Add onions and shallots; sauté 6 minutes
Add garlic; sauté 1 minute
Add broth
Cook 4 minutes or until onions are tender and liquid almost evaporates
Add beans and vinegar; cover and cook 4 minutes or until beans are crisp-tender
Remove from heat
Stir in remaining 1 teaspoon butter and 1/8 teaspoon salt
Keep warm

Sprinkle steaks with remaining 1/8 teaspoon salt and pepper
Heat a cast-iron skillet over medium-high heat
Coat pan with cooking spray
Add steaks to pan; cook 3 minutes on each side or until desired degree of doneness
Let stand 5 minutes. Serve with bean mixture