Salisbury Steak with Mushroom Gravy

Ingredients (18)

• 1/4 cup Italian breadcrumbs
• 2 Tbsp grated onion
• 2 Tbsp beef broth
• 1 lb ground beef/chuck
• 1 Tbsp dijon mustard
• 1 egg
• 1 tsp Worcestershire sauce
• 1 tsp kosher salt
• 1/2 tsp black pepper
• 1/2 tsp garlic powder
• 2 Tbsp olive oil
• Mushroom Gravy:
• 4 Tbsp unsalted butter
• 1 yellow onion
• 8 oz portabella mushrooms
• 2 garlic cloves
• 2 Tbsp AP flour
• 2 cups beef broth