Preheat your oven to 350°F (175°C). Grease the sides of an 8-inch round springform cake pan with vegetable oil or non-stick spray and line the bottom with parchment paper.

In a large mixing bowl, whisk together the flour, baking powder, and granulated sugar until smooth and free of lumps.

Add the water, vegetable oil, vanilla extract, and lemon zest (if using) to the dry ingredients and stir gently until well combined.

Pour the batter into the prepared springform pan and bake for 40-45 minutes, until golden brown and a toothpick comes out clean.

Remove the cake from the oven and let it cool in the pan for about 10 minutes before transferring it to a wire rack.