Whisk chickpea flour and water together in a bowl until smooth; let sit at room temperature, 2 to 6 hours.
Preheat oven to 450 degrees F (230 degrees C). Spray the inside of an 8-inch metal pie pan.
Skim foam from the top of chickpea-water mixture. Add oil, Italian seasoning, and rosemary and stir until combined. Pour mixture into the prepared pan; sprinkle black pepper and salt over the top.
Bake in the preheated oven until edges begin to brown, about 15 minutes. Remove bread from pan and cut into wedges.
