Japanese Burger Steak Gelson's

Ingredients

• 2 Tbsp Worcestershire sauce
• 1 Tbsp granulated sugar
• 5 Tbsp ketchup, divided
• 2 Tbsp oyster sauce
• 2 Tbsp canola oil, divided
• ½ yellow onion, small diced
• 1 lb ground beef
• ½ tsp kosher salt
• ½ tsp fresh ground black pepper
• ½ tsp ground nutmeg
• ⅓ cup panko breadcrumbs
• 2 Tbsp whole milk
• 1 Gelson’s large egg
• 6 Tbsp red wine, divided
• 1 Tbsp unsalted butter
• 3 Tbsp vegetable stock
• 4 cups mashed potatoes, divided, for serving
• Chopped fresh parsley, for garnish