In a food processor, add chickpeas and 1/4 cup of reserved chickpea liquid. Process until smooth.
In a mixer with paddle attachment, on medium speed, add pureed chickpeas and remaining ingredients. Mix 30 seconds or until well combined. Do not overmix.
Into a 8 x 8 baking pan coated with cooking spray, spread batter.
Bake until wooden pick inserted in center comes out clean, 28 to 30 minutes.
Cool completely on rack and then refrigerate 2 hours before cutting.