Preheat the oven to 140°C (275°F, gas mark 1). Grease and line an 18cm (7 inch) square cake tin.
To make the fudge brownie mix melt the extra dark chocolate in a microwave on medium power for 30 seconds at a time, stirring each time until melted, or in a heat proof bowl on a gentle heat over a bain marie. Leave to cool.
Beat the butter and sugar together in a stand mixer with paddle attachment or electric hand beater for approx. 2 minutes until pale and fluffy. If you haven't got an electric mixer you can do this with a wooden spoon in a bowl.
Add your eggs on a slow speed about a third at a time, mixing until combined.
Add your cooled chocolate stirring continuously. Add the vanilla Extract and stir. On slow speed mix in the flour until just combined. Do not over beat. Alternatively fold in by hand.
Pour the mix into your cake tin and bake for approx 40 mins. Check it with a sharp knife or metal skewer. You want this to be slightly under baked, so the knife should come out pasty, with a nice paste on the knife.
Leave to cool, then turn out into a bowl and crumble with your hands to fine fudgy crumb.
To make the cake balls, take a handful of fudge cake mix and squeeze together tightly - you are aiming for little balls about the size of a large walnut, approx. 30g each. If the mixture is dry, the addition of a little chocolate or vanilla butter cream will help the mixture stick.
Once you have all of your balls ready, dip the end of your stick into the melted chocolate chips and push the stick into each ball, about half way in. Hold the ball to stop it splitting open when the stick goes in.
Once all the cake pops are ready, refrigerate them for 1-2 hours before dipping them, or pop into the freezer for 30 mins, so the balls are firm enough to hold when dipping in the coating.
To coat the cake pops melt Dr. Oetker Fine Cooks White Chocolate on low power in a microwave bowl until just melted - stirring occasionally or over a bain marie on a gentle heat.
Plunge each cake pop into the chocolate coating until completely covered. Tap the cake pop gently on the side of the bowl to shake off the excess. Once all are covered, dip each cake pop again.
To decorate the ghosts roll out half the white regal icing into a large rectangle using plenty of icing sugar and a large plastic rolling pin. Roll fairly thinly - 2 to 3mm thick. Squeeze a little Dr. Oetker White Designer Icing onto the tops of the cake pops or brush with some melted white chocolate, to aid sticking of the sugar paste.
Using a cake cutter or small bowl, cut out circles of regal icing and place on each of the pops, smoothing down with your fingers to create the white sheet effect. Allow a little wavy movement by using your fingers to create smooth creases around the sides. Leave to set for a few hours to dry.
To add the ghostly expression take some Dr. Oetker black gel colour and squeeze out the eyes and mouth shapes. Leave these to dry overnight.