Place the lime rind in a small bowl or cup. Pour the boiling water over it and let steep for about 10 minutes.
Beat the eggs until light and fluffy.
Add the condensed milk and mix until well combined.
Add the white rum, cinnamon, nutmeg, and Angostura bitters. Mix well.
Strain the lime-infused water into the mixture, discarding the lime rind. Mix again until everything is thoroughly combined.
Pour the ponche de crème into clean bottles. If reusing bottles, sterilize them with hot water first and allow them to drain. You can also reuse the empty rum bottle.
Serve over crushed ice.