How to Make It
Pour the water into a bowl. Slowly whisk in the chickpea flour until smooth. Let stand at room temperature for 2 hours.
Preheat the oven to 500°. Skim any foam off the batter. Stir in the salt, rosemary and 1/4 cup plus 2 tablespoons of the oil.
Heat two 10-inch cast-iron skillets in the oven for 10 minutes. Carefully add 2 tablespoons of the oil to each skillet, swirling to coat. Divide the batter between the skillets; it should be less than 1/2 inch thick. Bake for 25 to 30 minutes, until crisp around the edges. Slide the farinata onto a board; cut into wedges. Sprinkle with pepper; serve.