Instructions

Combine ⅔ cup chilled heavy cream and 2 ounces soft licorice candy, chopped in medium saucepan. Bring to boil over medium heat. Remove from heat. Transfer to blender and process until smooth, 1 to 2 minutes, scraping down sides of blender jar as needed. Transfer to bowl and cool to room temperature, at least 30 minutes. Wash and dry blender jar.
When licorice mixture is cool, process remaining 2 cups cream in blender until soft peaks form, 20 to 30 seconds. Scrape down sides of blender jar and continue to process until stiff peaks form, about 10 seconds longer. Using silicone spatula, stir in 1 cup condensed milk, ¼ cup whole milk, ¼ cup light corn syrup, 2 tablespoons sugar, 1 teaspoon vanilla, and ½ teaspoon table salt. Process until thoroughly combined, about 20 seconds, scraping down sides of blender jar as needed. Remove two-thirds of plain cream mixture and set aside. Add licorice mixture to remaining cream mixture in blender. Add ⅛ teaspoon black food coloring, if using. Blend until fully combined, about 5 seconds.
Pour one-third of reserved plain cream mixture into 8½ by 4½-inch loaf pan. Drizzle half of licorice mixture on top. Top with another one-third of plain cream mixture followed by remaining licorice mixture, then finish with remaining one-third of cream mixture. Drag skewer through cream mixture in rough zigzag pattern all the way to bottom of pan. Press plastic wrap flush against surface of cream mixture. Freeze until firm, at least 6 hours. Serve.