Whisk together the chickpea flour, salt and pepper in a large bowl

Slowly add the water and whisk to combine. Cover and allow the mixture to rest for at least 2 hours and preferably overnight. (If resting the batter for more than 2 hours, store it in the refrigerator.)

When you are ready to bake the calentita, preheat the oven to 400°F. Pour the olive oil in the bottom of a 9x13-inch glass or metal baking dish and swirl it around to coat the bottom. Place the baking dish in the oven while it is preheating so that the dish can get very hot.

When the oven has reached the desired temperature and the baking dish is quite hot, carefully, remove the baking dish from the oven and pour the calentita batter into the dish. Return the dish to the oven.

Bake the calentita until firm and golden brown on the top, 55 to 60 minutes. Remove from the oven and cut into squares. Serve immediately.