In a mixing bowl, combine sweetened condensed milk with vanilla bean paste. In a separate bowl, whip the cream until stiff peaks form. Gently fold the condensed milk mixture into the whipped cream, then mix in the sliced blackberries. Pour the mixture into a loaf pan, cover, and freeze for at least 7 hours or overnight until firm.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. In a medium bowl, whisk together flour, baking soda, salt, and cinnamon. Cream softened butter with cane and brown sugars until fluffy. Mix in the egg and vanilla, then combine with the dry ingredients and oats. Drop tablespoons of dough onto the baking sheet and bake for 9-10 minutes until lightly golden.

Once baked, immediately flatten each cookie with a spatula. Allow them to cool completely on the baking sheet before transferring to a wire rack.

Scoop blackberry ice cream onto the flat side of one cookie, then press another cookie on top. Repeat until all cookies are paired. Freeze assembled sandwiches for about 30 minutes to firm up.

Melt dark and white chocolate chips with coconut oil in the microwave in short bursts, stirring until smooth. Drizzle over sandwiches once cooled slightly.

Once drizzle has set, slice sandwiches in half if desired, and serve immediately or store in the freezer.