Heat oven to 180°C fan (200°C conventional). Grease or line a 20cm square tin.

In a large bowl, stir together flour, sugar, cocoa, baking powder, and coconut (if using).

Pour in melted butter and golden syrup. Mix until thick and crumbly.

Spoon the mixture into the tin and press it down firmly and evenly.

Bake for 20–25 minutes until the top is set and slightly cracked.

Cool in tin for 10 minutes, then slice while still warm. Let it firm up as it cools.