1Blend cantaloupe, vodka, lime juice, and mint leaves in a blender until smooth; stir in sugar. Freeze cantaloupe mixture until slushy consistency, 45 minutes to 1 hour.
2Pour blackberry brandy into a martini glass; carefully spoon cantaloupe mixture over brandy, creating a contrasting orange layer.
Footnotes
Cook's Note:
I found the longer the cantaloupe froze the easier it is to make a layer of it in the glass. The first time making this I didn't need any sugar as the melon was perfect so definitely sample your melons to see if you would like to add sugar.