Bring milk, sugar to boil in heavy-bottomed saucepan, stirring occasionally.
Remove from heat, cool.
Before you open the coconut milk, shake canned coconut milk vigorously. (If you don't, there'll be a weird gelatinous layer on top and thin liquid below and it's murder to get it to smooth out. Trust me, it's a lot easier to shake that groove thang before you open the can.)
Stir coconut milk, rum into milk mixture. Freeze in
ice cream maker
.
Popular South American refreshment.