Preheat your oven to 180°C or 350°F and grease and line a 9x9 pan with parchment paper. Leave some overhang to make it easier to pull it out once it’s baked.
Whisk together the flour, baking powder, baking soda and salt and set aside.
In a separate bowl, whisk together the milk, sugar, chickpea flour, water and vanilla until completely smooth. If you see a few tiny lumps of chickpea flour that’s normal.
Add the coconut oil and whisk until it’s glossy and smooth.
Add the dry ingredients into the wet and combine. The batter will be fairly thick.
Place it in the pan and spread it out evenly with a spatula or the back of a spoon.
Sprinkle the top liberally with some coarse salt and bake for 25-30 minutes or until a toothpick inserted in the center comes out clean.
Let it cool in the pan for a few minutes before placing it on a wire rack to cool completely.