Bring the remaining 1 1/2 cups of water to a boil. Reduce the heat to medium-high and add the chickpea flour and water mixture. Whisk over the heat until the mixture becomes really thick and glossy. This should take about 8 minutes.
Pour immediately into the prepared baking dish and leave to cool at room temperature for at least 1 hour. The longer it sits, the more water will drain out of the tofu and the firmer it will get.
Cut into whatever size and shape you like. This will depend on how you are going to use it. I cut it into 2 to 3 cm cubes. Store in an airtight container and use within 3 days. Some commenters have had success freezing it, but it is not something I have tried myself.