Beat whipping cream on medium speed for about 4 minutes or until it starts to form soft peaks. Reduce speed to low and add in sweetened condensed milk and beat until combined.
Broil marshmallows on a foil lined baking sheet for 1 to 2 minutes until toasted. Careful: they burn QUICKLY so you need to babysit the oven. Quickly add the toasted marshmallows to the cream mixture and stir.
Pour into a freezer safe container. Freeze for at least 8 hours before serving.