Preheat 190°C/170°C fan/Gas Mark 5.
In the bowl of a stand mixer, beat the butter and sugar together until light and fluffy. Gradually add in the eggs and then follow with the self-raising flour, baking powder and vanilla. Beat well until combined and then split into two bowls.
For the chocolate mixture, add in the cocoa powder, chocolate chips and milk and place in a piping bag.
For the peanut butter mixture, beat through the peanut butter and the food colouring until you have a rich golden colour. Transfer to a piping bag.
Grease the cake tin well and start to fill. Cut the ends of the piping bag off, just big enough for the chocolate chips to come out and cut the other bag the same.
Starting with the peanut butter mixture, pipe a little of the mixture in alternate grooves halfway up the tin and follow by piping a little of the chocolate mixture into the other grooves, again halfway up the tin. Go back over the original lines with more peanut butter and repeat the process until all the mixture is used up.
Smooth the top of the mixture with a palette knife and then bake for 25 minutes.
Once it is cooked, allow to cool for 5 minutes in the tin and then remove to cool completely.
While the cake is baking, make the chocolate glaze by heating the double cream until just below a simmer and then pour over the chocolate. Allow to sit for 3-4 minutes and then stir well. Allow to chill for 4-5 minutes until slightly set, but still runny.
Once the cake is cool, pipe or spoon the chocolate glaze over the top and let it drip down the sides. Chop the peanuts and sprinkle on top. Serve.