Add the mint, heavy cream, and salt to a saucepan.
Heat over medium heat until just warmed; do not allow the mixture to simmer or boil. Remove the saucepan from heat and steep for 10–20 minutes to infuse the mint into the cream.
Strain the leaves and transfer the cream to a large bowl.
Cover the surface of the cream with plastic wrap and chill until completely cooled, about 2 hours.
Once cooled, whip the cream into stiff peaks.
In another bowl, whisk together the condensed milk, vanilla, and bourbon.
Whisk the condensed milk mixture into the whipped cream until combined.
Transfer to a loaf pan or baking pan and cover. Freeze until solid, about 6–8 hours.