1 can (14 ounces) sweetened condensed milk
2 teaspoons pure vanilla extract
2 tablespoons bourbon (optional)
2 cups cold heavy cream
In a medium bowl, stir together condensed milk, vanilla, and Bourbon, if desired.
In a large bowl, using an electric mixer, beat cream on high until stiff peaks form, 3 minutes.
With a rubber spatula, gently fold whipped cream into condensed milk mixture.
Pour into a 4 1/2-by-8 1/2-inch loaf pan. Freeze until firm, 6 hours.
Note: Freeze, covered, up to 1 week.