Preheat oven to 180C
For the chocolate cake base, add all ingredients to a small bowl and mix until combined. Pour into a small lined tray then bake for 7-10 minutes or until cooked. Remove from oven and cool.
For the peanut butter cookies, prepare and bake according to recipe. Remove from oven and cool.
For the ice cream cake, crumble the chocolate cake into a bowl and add ½ cup peanut butter ice cream. Mix until just combined and press into a lined 15cm cake tin. Put aside in the freezer to firm up.
For the next layer, soften one ice cream flavour at room temperature. Spread over first layer, crumble half of the peanut butter cookies on the surface and gently press in. Return the cake tin to the freezer.
For the final layer, soften the second ice cream flavour at room temperature. Scoop into cake tin and return to the freezer.
When the top layer has completely frozen, remove the cake from the freezer then remove from the tin. Gently melt the chocolate over a double boiler and drizzle over cake.
To decorate, use remaining ice cream, peanut butter cookies and cones to make ice cream sandwiches and/or ice cream cones. If the cake begins to melt, return it to the freezer until solid. Place decorations on cake and enjoy!