Preheat oven to 180 degrees celsius.
Line 2 flat cookie baking trays with baking paper and set aside.
Place the chopped butter and chocolate melts into a microwave safe bowl.
Place into the microwave and heat for 3 minutes (or until just melted) on 50% power, stirring every 30 seconds with a metal spoon.
Place the eggs, caster sugar, cocoa powder and vanilla extract into a large bowl.
Beat with handheld beaters or a stand mixer for 3 minutes.
Slowly add the melted chocolate mixture to the egg mixture beating in between additions.
Add the salt, baking powder and sifted plain flour.
Mix until just combined.
Add the peanuts and fold through with a spatula.
At this stage the mixture will be very thin (almost like a cake batter).
Place tablespoonfuls of the mixture onto the prepared trays.
The cookies will spread so make sure you leave a 3-4cm gap between each cookie.
Bake for 12 minutes.
Remove from the oven and leave on the baking trays for a further 10 minutes (they will continue to cook).
Use a flat spatula to transfer the cookies to a wire rack to cool completely.
When the cookies have cooled completely, place spoonfuls of ice-cream between two cookies and gently squeeze together.
Serve immediately or place into an airtight container in the freezer until required.