3/4 cup cubed cantaloupe
1 (1.5 fluid ounce) jigger vodka
1 tablespoon fresh lime juice
4 fresh mint leaves, coarsely chopped
1/8 teaspoon raw sugar, or to taste (optional)
1 fluid ounce blackberry brandy
Blend 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.
Pour blackberry brandy into a martini glass; carefully spoon cantaloupe mixture over brandy, creating a contrasting orange layer.