Mix water with chickpea flour, 1 tablespoon olive oil and salt. Cover and let stand for 2 hours at room temperature.
Preheat oven to 240 degrees C. Heat a heavy based or cast iron frying pan.
Remove the foam off the top of the batter. Stir in rosemary.
Add 2 tablespoons olive oil to the hot frying pan and fill with the batter. Carefully return the tin to the oven and bake for 25 minutes until golden-brown and crispy. Serve warm.