Korokke (Potato & Meat Croquette)

Bahan-bahan (6 porsi)

• 2 lb russet potatoes ((about 4 potatoes))
• 1 onion
• ½ carrot
• 2 shiitake mushrooms
• 2 Tbsp neutral oil ((for sautéing))
• 1 lb ground beef
• 1 tsp Diamond Crystal kosher salt
• ¼ tsp white pepper powder
• freshly ground black pepper ((to taste))
• 1 large egg (50 g w/o shell)
• ½ cup all-purpose flour (plain flour)
• 3 large eggs (50 g w/o shell)
• 2 cups panko (Japanese breadcrumbs)
• 3 cups neutral oil ((or enough for 2 inches (5 cm) of oil to completely submerge the patties))
• tonkatsu sauce ((you can make Homemade Tonkatsu Sauce))