Socca

Preheat broiler with rack 8 inches from heat. Stir together flour, 2 cups water, the oil, and 1 tablespoon salt.

Oil a 12-inch cast-iron skillet; pour in batter. Broil until golden brown, 3 to 4 minutes. Bake at 400 degrees, until set, about 6 minutes. Sprinkle with rosemary; season with salt and pepper. Cut into 8 wedges.