They are made from flour stuffed with meat and vegetables. This filling is called "so" (소). Pork is the most common meat for "so", but beef, chicken, or pheasant can also be ingredients of "mandu". Vegetables are typically carrots, cucumbers, onions, and bean sprouts. Other additional ingredients are kimchi, tofu, or chopped noodles made from sweet potatoes. They can be fried, boiled, steamed or even baked, and each type has a different name. "Mandu" are usually served with soy sauce mixed with vinegar for dipping.