A Classic Loco Moco

Ingredients

• Egg
• 2 tbsp unsalted butter
• 1/2 medium sized sweet onion (optional
• 3/4 cup sliced mushroom (optional)
• green onions (for garnishing)
• cooked rice
• 1 1/2 lb ground beef
• 1 tbsp Worcestershire sauce
• 1 1/2 tsp seasoning salt
• 1 tsp garlic powder
• 1/2 tsp black pepper
• 1 1/2 cup beef stock
• 4 tsp shoyu (soy sauce)
• 1 tsp Worcestershire sauce
• 2 tsp ketchup
• 5 tsp cornstarch