In a heavy, medium saucepan over medium heat, combine the cream/half and half, milk and sugar. Bring almost to a simmer, stirring often until the sugar has dissolved.

Remove from heat and add the mint leaves, stirring them into the liquid. Allow to sit for 1 hour.

Strain and add the vanilla. Chill until fully cold for a few hours in the refrigerator or overnight. Once chilled, process in an ice cream maker according to the manufacturer’s instructions. Once complete, spoon into a freezer proof container and chill overnight.

Prepare a baking sheet lined with parchment or waxed paper. Scoop the ice cream into 2-inch balls, place on the prepared pan and return to the freezer for them to become solid (2 hours or longer).

Place 3 ice cream balls in a chilled 8 ounce Julep cup. Pour in the bourbon and fill with seltzer water.