caramel:
3 tbsp water
1 tsp lime juice
1/2 cup granulated sugar
custards:
175 g sweetened condensed milk
4 large egg yolks
3 tbsp lime juice
1 tsp lime zest
1 tsp vanilla extract
To serve, run a palette knife around the inside edge of the ramekin to loosen the custard. Place a plate over the ramekin and then invert both, tapping the ramekin gently so that the custard releases onto the plate.