Whisk the warm water into the chickpea flour until smooth. Add the salt, pepper and minced rosemary and whisk again. Allow to sit on the counter for 4 hours (or overnight) to allow for a complete absorption of the water by the chickpea flour.
A foam may develop on the surface of the batter. If so, gently remove with a spoon. Whisk in the Rosemary Olive Oil.
Preheat the oven to 400˚F, and move the rack to the top third of the oven.
Add the olive oil to a very well seasoned pan that's oven proof (I used a well used cast iron skillet). Sauté the garlic until it just starts to turn a golden brown. Pour in the batter and jiggle the pan to even out the batter. It will start to sizzle immediately. Cook on the stovetop another 30 seconds, and transfer the pan to the oven.
Bake for 10 - 12 minutes, until the edges start to curl up and brown slightly. The top may lightly crack in a few places. Remove and immediately and either flip out with a spatula and slice into pie-shaped pieces, or scrape up roughly to break it up into irregular pieces, and toss onto a plate in a pile for picking up with the fingers.