Dry spiced tofu (dou fu gan) is tofu that has been marinated in some sort of spice mixture (often five-spice) and either pressed under great pressure or baked to remove as much moisture as possible. This gives it an extremely dense and "meaty" texture.
Where do I find dry spiced tofu?
You will usually need to visit an Asian market to find dry spiced tofu. It's sold in the refrigerated section under a variety of names but can easily be spotted if you know what to look for. It comes in the form of reddish-brown bricks or cakes that have been vacuum packed.
You may also be able to find baked tofu at natural food stores or conventional grocery stores. It will have a similar texture but often a different taste. West Soy is a brand that makes baked tofu.