Easy Homemade Salisbury Steak

Ingredients

• 2 pounds ground beef (80/20)
• 1 tablespoon olive oil
• 1/2 white onion, minced
• 2 tablespoons butter
• 2 slices white bread
• 1/2 cup heavy whipping cream
• 1 1/2 teaspoons kosher salt
• 1 teaspoon black pepper
• 1 1/2 teaspoons garlic powder
• 2 to 3 dashes Worcestershire sauce
• 1 egg, beaten
• 1 1/2 tablespoons fresh parsley
• 1 pound sliced button mushrooms
• 1/4 white onion, thinly sliced
• 1 tablespoon butter
• 2 tablespoons flour
• 1 package beefy onion soup mix (only the powder)
• 2 1/2 cups beef stock, plus
• 2-3 dashes Worcestershire sauce
• 2 teaspoons Dijon mustard
• 1/2 teaspoon salt
• 1/2 teaspoon black pepper