Nikkei Beef Empanadas

Name: Nikkei Beef Empanadas
Ingredients: 8 tbsp canola or any other neutral oil, plus two tbsp.; 1 cup onions, roughly chopped; 1 lb ground beef; 4 tbsp tomato paste; Kosher salt, to taste; 1 cup shiitake mushrooms, chopped; 1 tbsp aka miso (red miso); 1 tbsp mirin; 2 tbsp kimchi juice; 2 tbsp aji amarillo pepper purée; 4 tbsp soy sauce; 1 cup fresh tomatoes, diced; 4 tbsp curly parsley, finely chopped; 3 hard-boiled eggs, grated or roughly chopped; 1 lb pastry dough, rolled out and cut into 4-inch discs; 1 uncooked egg