01 -
Preheat oven to 175°C and grease a 23-centimetre square baking dish. Set aside.
02 -
In a medium bowl, whisk together all-purpose flour, granulated sugar, cocoa powder, baking powder, and salt until homogenous.
03 -
Add milk, vegetable oil or melted butter, and vanilla extract to the dry ingredients. Stir with a spatula until a smooth, thick batter forms. Transfer batter to the prepared pan and spread evenly.
04 -
In a separate bowl, blend granulated sugar, light brown sugar, and cocoa powder for the topping. Distribute evenly over the cake batter in the pan without mixing.
05 -
Carefully pour boiling water over the entire surface of the pan, avoiding disruption of the layers by pouring gently over the back of a spoon. Do not stir.
06 -
Place pan in the centre of the oven and bake for 35 to 40 minutes, until the surface is just set while the base remains fudgy.
07 -
Remove from oven and allow to stand for 10–15 minutes. Serve warm by scooping portions to reveal the rich fudge sauce underneath. Optionally, finish with a scoop of vanilla ice cream.