Beef Patties with Gravy Recipe

Ingredients

• 1 large egg, room temperature
• 2 green onions with tops, sliced
• 1/4 cup seasoned bread crumbs
• 1 tablespoon prepared mustard
• 1-1/2 pounds ground beef
• 1 jar (12 ounces) beef gravy
• 1/2 cup water
• 2 to 3 teaspoons prepared horseradish
• 1/2 pound fresh mushrooms, sliced
• Minced fresh parsley, optional