Preheat oven to 180˚C/ 160˚C fan-forced.
Grease and line a 20cm square cake pan with baking paper.
Place chocolate in a heatproof bowl over a saucepan of simmering water. Stir until smooth.
Scoop avocado flesh into a large bowl and add lemon juice.
Using a stick blender, blend avocado until smooth (it is important to not have any lumps).
Add sugar, eggs, cocoa, flour, baking powder and chocolate to avocados. Mix until well combined.
Pour mixture into prepared pan. Bake for 25 minutes or until just set. Allow brownie to cool completely in pan.
Place ice-cream into a bowl and stand at room temperature until just softened.
Scoop avocado flesh into a bowl; add lemon juice and mash until almost smooth.
Stir avocado through ice-cream until just combined
Spoon into an airtight container.
Freeze for 3-4 hours or until ready to serve
Serving Size 6