Open Faced Mushroom and Onion Steakburgers Recipe

Ingredients For Open Faced Mushroom and Onion Steakburgers Recipe

• 21 inch 1 soft french baguette
• 4 tablespoon Unsalted butter softened
• 1 teaspoon Garlic salt
• 10 Thick slices gruyere or cheddar cheese cut in 1/2 and divided
• 2 pound Extra lean ground sirloin
• 1 tablespoon Steak sauce i. e. a 1
• 1.5 teaspoon Steak seasoning
• 1 Large egg
• 2 tablespoon Olive oil
• 8 ounce 1 container sliced baby portabella
• 1 Large sweet onion thinly sliced
• 1 tablespoon Balsamic vinegar
• 2 teaspoon Fresh thyme leaves
• 0.25 teaspoon Sugar
• As required Salt and black pepper to taste