Cafe The Ttin Ttu is a cafe in Gwanak-gu, Seoul, about a 4-5 minute walk from Exit 1 of Seoul National University Station on Seoul Subway Line 2. It serves coffee and Hong Kong-style waffles, with an americano that is nutty without acidity and a plain Hong Kong waffle that is crisp outside and soft inside, served with cream and maple syrup. The underground cafe is entered through a wardrobe door and has turntables and sofas. Each seat has a power outlet and a wide desk, so many customers work on laptops.