Preheat the oven to 160°C (320°F) for convection or 180°C (355°F) for standard. Grease and line a 20 cm (8-inch) cake tin.

In a bowl, whisk together milk and vinegar, letting it sit for 5-10 minutes. Add canola oil, eggs, brown sugar, and caster sugar, whisk until combined.

Sift flour, cocoa powder, baking powder, and salt into the bowl with the wet mixture. Fold gently until just combined.

Gradually add boiling coffee or water, whisking until the batter is smooth and thin.

Pour batter into the prepared tin and bake for 55-60 minutes. Check for doneness with a skewer.

Allow the cake to cool in the tin for 20 minutes, then transfer to a wire rack to cool completely.