Place a 9x5x2-inch loaf pan in the freezer while you assemble the ice cream.
In a food processor fitted with the blade attachment, process the cream cheese, vanilla and salt until smooth, scraping the bowl as needed. Add the heavy cream and process until stiff peaks form.
Add the sweetened condensed milk and process just until combined.
Transfer the ice cream to the cold pan and smooth the top. Dollop about 1/4 cup of hot fudge sauce over the ice cream base and use a fork to swirl it throughout, making sure the swirls reach the bottom of the pan. Then dollop another 1/4 cup of hot fudge sauce over the top and swirl it across the surface decoratively. This makes for the prettiest of ice creams.
Cover in plastic wrap and freeze for at least 6 hours, but preferably overnight
The ice cream will keep in the freezer for a week, tightly covered in plastic wrap.