This "hidden cafe" makes the best ca phe truong (egg coffee) in Hanoi. A few blogs claimed that tourists have discovered this spot, but it was all locals chain smoking when we sat down to have our shockingly strong black coffee. The egg white version is super and thick like a melted marshmallow, so we ordered two regular hot coffees and spooned in the sweetened egg whites. Behind the counter, coffee drips slowly into giant jars. It comes out with an incredible and robust coffee flavor. For 15k per cup (70 cents), I will definitely struggle to pay for a $4 espresso again.