Salisbury Steak {A Classic!}

Ingredients

• 1 pound ground beef
• 1/3 cup plain breadcrumbs
• 1 large egg
• 1/2 teaspoon salt
• 1/4 teaspoon ground black pepper
• 2 tablespoons neutral-flavored oil cooking oil (I use avocado oil)
• 8 ounces crimini or brown mushrooms, sliced
• 1 small yellow onion, sliced
• 1 clove garlic, chopped
• 2 tablespoons tomato paste
• 1 1/2 teaspoons prepared yellow mustard
• 1 1/2 cups low sodium beef broth
• 2 teaspoons cornstarch
• 1 tablespoon water
• 2 tablespoons chopped fresh parsley, for garnish (optional)