Preheat oven to 160 degrees celsius (fan-forced). Grease the base and sides of a loose-bottomed 23cm tart tin and place onto a flat baking tray. Set aside.
Place the butter (chopped) into the Thermomix bowl and melt for 3 minutes, 80 degrees, Speed 2. Add the biscuits and crush on Speed 8, 10 seconds. Pour the mixture into the prepared tin and then press firmly onto the base and sides. Note: Use a spoon or a round cup to press the mixture firmly into the tart tin.
Place into the oven for 10 minutes before removing and setting aside to cool slightly.
To make the filing, place the golden syrup, condensed milk and butter into a clean and dry Thermomix bowl. Mix on 80 degrees, Speed 4, 8 minutes.
Pour the caramel into the tart shell and bake for a further 15-20 minutes or until golden. Allow to cool.
To make the chocolate ganache, break the chocolate into chunks and place it into a clean and dry Thermomix bowl. Add the cream and cook on 60 degrees, 3 minutes, Speed 2.
Allow the ganache to cool for 10 minutes or until slightly thickened (place into the fridge if needed).
Pour the chocolate ganache over the tart, place into the fridge for 10 minutes and then decorate with mini Easter eggs and place back into the fridge to set for 2 hours.
Allow the tart to come to room temperature before serving.