Combine the condensed milk and cinnamon in a medium bowl. Set aside.
Whip the heavy cream in a medium bowl until stiff peaks form. Gently fold the whipped cream into the condensed milk mixture. Transfer to a 9-by-13-inch glass baking dish and cover with plastic wrap. Freeze without stirring until firm, at least 6 hours or overnight.
Scoop into bowls. Top with candied pecans.
Photograph by Con Poulos