Mandu (Korean Dumplings)

Ingredients

• 8 ounces medium-firm tofu
• 8 ounces ground pork
• 8 ounces ground beef
• 2 cups buchu (Korean garlic chives), finely chopped
• 1/2 medium yellow onion, finely chopped
• 3 cloves garlic, minced
• 1 tablespoon fresh ginger, minced
• 1 large egg
• 1 tablespoon soy sauce
• 1 tablespoon toasted sesame oil
• 1 teaspoon salt
• 1 teaspoon white or black pepper
• Flour, for sprinkling
• 1 package (50 to 60 wrappers) store-bought or homemade mandu wrappers
• 2 tablespoons vegetable oil, for pan frying
• 4 tablespoons soy sauce
• 4 tablespoons rice vinegar
• 1 scallion, trimmed and thinly sliced
• 1 clove garlic, minced
• 1 teaspoon sesame oil
• 1 teaspoon toasted sesame seeds
• 1/2 teaspoon gochugaru (Korean chili flakes), optional