Method:
1 Preheat oven 160°C fan-forced.
2 Combine ice cream and saffron in a bowl stir to combine. Return to freezer until ready to serve.
3 Whisk cornflour and eggs in a bowl heatproof bowl until smooth. Combine condensed milk, lemon rind, a pinch saffron and boiling water in a saucepan over medium heat, cook stirring until warm. Pour over the egg mixture, stirring constantly until combined. Return to saucepan and cook, stirring, over low heat for 4-5 minutes or until thickened. 
4 Pour mixture into heat proof ramekins and bake for 10 minutes or until firm, refrigerate until cold.
5 Sprinkle tops of custards with caster sugar, using a kitchen blow-torch caramelize the sugar, top with a scoop of saffron ice cream to serve.