Preheat your oven to 350°F (175°C).
Grease a pudding basin with butter or spray and line it with greaseproof paper.
In a large bowl, combine flour, sugar, cocoa, baking powder, and salt.
Add in the eggs, butter, water, and vanilla extract.
Mix with a hand mixer or whisk until smooth and well blended.
Pour batter into prepared pudding basin.
Bake for 30–35 minutes or until a toothpick inserted comes out clean.
Let the cake cool completely before removing from basin.
Trim a small piece off the side to create a flat base for your hedgehog.
Prepare frosting by mixing icing sugar, cocoa, soft butter, and milk until smooth.
Spread frosting evenly over the cooled cake with a spatula.
Insert chocolate chips or sprinkles to create hedgehog’s “spikes”.
Attach candy eyes and a chocolate button for the nose.
Optional: pipe green-tinted frosting at base to resemble grass.
Serve and enjoy your hedgehog-shaped chocolate cake with friends and family.