Double Dark Chocolate No-Churn Ice Cream

Whisk ¼ cup light corn syrup, 3 Tbsp. heavy cream, ½ tsp. vanilla extract, and ¼ tsp. Diamond Crystal or Morton kosher salt in a small microwave-safe bowl until smooth. Add ⅔ cup semisweet chocolate chips and microwave on high in 10-second bursts, stirring after each burst, until melted and smooth, about 1 minute total. Whisk fudge sauce until glossy and smooth, then let cool. It should be very thick but still pourable. (Alternatively, heat ingredients in a small saucepan over medium, whisking constantly, until chocolate is melted and sauce is smooth. Let cool.)

Chill a 9x5" or 8½x4½" loaf pan until cold, about 10 minutes.

Meanwhile, blend one 14-oz. can sweetened condensed milk, 2½ cups heavy cream, ¾ cup Dutch-process cocoa powder, 2 Tbsp. vanilla extract, 2 Tbsp. vodka, and 1½ tsp. Diamond Crystal or ¾ tsp. Morton kosher salt in a blender, starting on low speed and gradually increasing to medium and scraping down sides as needed, until aerated and very fluffy like mousse, about 1 minute. (Mixture will stick to sides of blender and no longer move when done.)

Scrape about one third of ice cream base into chilled loaf pan and smooth into an even layer with a spoon. Transfer fudge sauce to a pastry bag and pipe about one third of fudge evenly over in thick ribbons. (Alternatively, use a spoon to drizzle the fudge over in thick ribbons.) Do not swirl. Spoon half of remaining ice cream base on top and smooth into an even layer. Pipe half of remaining fudge in thick ribbons on top, then repeat layers with remaining ice cream mixture and fudge and swirl as desired. Freeze ice cream, uncovered, at least 6 hours.

When ready to serve, let ice cream sit at room temperature 10 minutes before scooping into bowls. Do Ahead: Ice cream can be made 1 week ahead. Cover and keep frozen.