Lightly oil a 9-inch square cake pan or casserole. A round pan works, too. In France I’ve seen them cool the stuff on a slab, even.
Heat the water with the oil and salt in a saucepan. Once hot, but not boiling, whisk in the chickpea flour. If there are some small lumps, don’t worry. This is a very forgiving process.
Whisk over medium heat until the mixture thickens, about three minutes.
Switch to a wooden spoon, and continue to cook, stirring constantly, for 10 minutes until very thick and the batter is very thick.
Scrape into the oiled pan and let cool. You can let sit on a counter until stiff, or refrigerate for a couple days, covered.
To fry the panisses, unmold on a cutting board and slice into French fry-sized sticks. Again, this is your call. Thinner seems to be more popular.
In a heavy-duty skillet—I use cast iron— heat 1/4-1/2 inch of olive oil. When hot, fry the panisses in batches, not crowding them in the pan. Once the bottom is nicely browned and crisp, turn with tongs, frying the panisses until they are deep-golden brown on each side.
Remove from pan and drain on paper towels, sprinkling them very generously with salt and pepper.