Skinny Salisbury Steak with Mushroom Gravy

Ingredients (18)

• 1 1/2 tsp oil
• 3/4 cup onions
• 1  lbs  93% lean ground beef
• 1 lb 93% lean ground turkey
• 1/2  cup  unseasoned breadcrumbs
• 1 large egg
• 1 large egg white
• 2 cups beef broth
• 1/4  tsp  salt
• 1/8  tsp  ground black pepper
• 8 oz sliced mushrooms
• 2  tbsp  all-purpose flour
• 2 tbsp tomato paste
• 1 tsp red wine vinegar
• 2  tsp  Worcestershire sauce
• 1/2  tsp  mustard powder
• 1/4  cup  water
• chopped parsley for garnish