To freeze the cake 1 to 2 weeks ahead, make, cool and glaze the cake. Freeze it for about an hour, then cover the cake tightly and freeze for up to 2 weeks. To thaw, unwrap the cake and allow it to stand at room temperature for 2 hours. Garnish if desired.
To make white chocolate curls, pull a vegetable peeler against the long side of the bottom of a block of vanilla-flavored candy coating (almond bark). If the curls break, place the block in a warm place for about 20 minutes to soften it for better curls.
Be sure to buy sweetened condensed milk, not evaporated milk. They don't work the same way in recipes.