Sirloin Steak 'N Onions

Ingredients

• 1 tablespoon olive oil
• 1 1/2 teaspoons dried onion flakes
• 1 teaspoon garlic powder, divided
• 3/4 teaspoon dried rosemary, divided
• 3/4 teaspoon salt, divided
• 1/4 teaspoon pepper, plus
• 1/8 teaspoon pepper, divided
• 1 1/2 lbs boneless sirloin steaks, about 1 1/2 inches thick
• 2 tablespoons butter, divided
• 1 medium red onion, cut into 6 wedges
• 1 yellow onion, cut into 6 wedges
• 1 shallot, chopped
• 1/2 cup red wine
• 1/4 cup chicken broth
• mashed potatoes, boxed or homemade