Make the cocoa mix:
In a saucepan, combine the sugar, cocoa powder and milk.
Bring the mixture to the boil, stirring constantly to dissolve the sugar and cocoa.
Once boiling, reduce the heat and simmer for 2 minutes.
Remove from the heat and add the butter and a pinch of vanillin, stirring until the butter is completely melted and the mixture is smooth.
Let the cocoa mixture cool to room temperature.
Shape into balls:

Pour the cooled cocoa mixture over the cookie and peanut mixture.
Mix thoroughly until all ingredients are well combined.
Lubricate your hands with vegetable oil to prevent sticking.
Shape the mixture into small balls about the size of a walnut.
Place the balls on a baking sheet lined with parchment paper.
Refrigerate for 1 hour to firm up.
Coat with chocolate:
In a double boiler or microwave, melt the dark chocolate and milk chocolate with the vegetable oil, stirring until smooth.
Dip each cookie ball into the melted chocolate, making sure it is completely coated.
Return the chocolate-covered balls to the parchment-lined baking sheet.