Using a medium saucepan over medium-high heat, combine the blackberries with ¼ cup sugar and 2 Tbsp. of water. Using a potato masher or a wooden spoon, mash the berries slightly. Bring to a boil and reduce heat to a simmer, stirring occasionally, until berries begin to break down, about 5–10 minutes. Remove the berries from the heat and transfer the berries to a fine mesh sieve placed over a small bowl. Using a ladle, push the berries against the sieve, allowing the juices to run into the bowl. Discard the solids and return the juice to the saucepan over medium heat and reduce for about 5 minutes, leaving about ¾ cup blackberry juice. Set aside to cool. Transfer to an airtight container and refrigerate.

Using a clean medium saucepan over low heat, combine the milk, 1 cup cream, ½ cup sugar and vanilla pod and seeds. Bring the milk to a simmer and heat until sugar dissolves, stirring occasionally.

Prepare an ice bath. Set aside. Using a medium bowl, whisk egg yolks and remaining ¼ cup sugar. Gradually whisk 1 cup hot milk mixture into yolks, whisking constantly to prevent curdling. Whisk yolk mixture into remaining milk mixture in saucepan, whisking until combined. Cook over low heat, stirring continuously with a rubber spatula, until the custard thickens enough to coat the back of the spatula, about 7–9 minutes. Transfer custard to a medium bowl and place in the prepared ice bath to cool. Stir occasionally until cool. Remove vanilla bean pod from custard. Cover and refrigerate at least 4 hours or overnight.

Combine the blackberry puree and ice cream base. Place the frozen Ice Cream Maker Attachment onto the KitchenAid® Stand Mixer. Place the dasher inside the bowl. Connect the drive adaptor to the stand mixer motor head. Lower the tilt-head or raise the bowl, depending on your model, until the drive adaptor engages the dasher.

Turn the stand mixer on to speed 1 before adding the blackberry ice cream mixture. Pour the ice cream base into the freeze bowl with the dasher churning. After 15 minutes, add the chopped chocolate. Continue churning for 5–15 minutes until soft serve consistency is reached. Remove the dasher and scrape the ice cream off with a rubber spatula.

Place the blackberry chocolate chip ice cream in an 8.5-inch x 4.5-inch-wide metal loaf pan and smooth the top. Sprinkle with the flaky sea salt. Cover with plastic wrap and freeze for several hours until firm, or overnight. Scoop ice cream into bowls and garnish with fresh berries.