Remove the corn kernels from the cob with a knife. Then, carefully break the cobs in half with your hands.
Place the corn kernels in a food processor. Pulse several times until coarsely chopped.
Add the chopped kernels, cobs, 1½ cups (360 ml) of cream, and the salt to a large saucepan. Stir to ensure the ingredients are well combined. Cover and cook over low heat for 20 minutes.
Remove the cream and corn mixture from the heat and chill in the refrigerator for at least 2 hours.
Combine the blueberries, sugar, and lemon juice in a medium bowl. Let sit at room temperature for 10 minutes, or until the berries appear juicy and vibrant, stirring occasionally.
Transfer the berry mixture to a food processor or blender and puree. Set aside.
Remove the corn cobs from the chilled cream mixture. Pour the remaining corn cream through a sieve into a large bowl. Use the back of a spoon or spatula to press the solids to extract any remaining liquid.
Add the remaining heavy cream. Using an electric hand mixer, whip the cream mixture until soft peaks form. Fold in the condensed milk with a rubber spatula.
Pour half of the cream mixture into a 9x5-inch (23x13-cm) loaf pan. Top with half of the blueberry puree and use a knife to swirl it into the cream.
Top with the remaining cream and puree, then swirl the puree with a knife again.
Freeze for 3-4 hours before serving. If the ice cream is too solid to scoop, let sit at room temperature for 10-15 minutes before scooping.