Preheat an oven to 180°C. Grease a cake tin with a little butter and dust it with flour. In a bowl, cream sugar and butter together a hand blender. Add eggs one by one and blend till well mixed.
Add vanilla essence and cocoa powder. Beat well. Fold in the flour. Pour the batter in the greased cake tin and sprinkle the raisins and peanuts on top.
Bake in the preheated oven for twenty minutes or till done. Allow it to cool, cut into finger sized pieces and serve.