Start the rice pudding: In a medium pot, combine the milk, cider, rice, brown sugar, and salt over medium heat. Stirring frequently, heat the mixture to a simmer. Continue to simmer over medium-low heat, stirring frequently, until the rice is tender and absorbs most of the liquid and the liquid becomes thick, 25 to 30 minutes.
While the pudding cooks, make the candied pecan topping: In a medium pot, combine the granulated sugar with the cinnamon, 1/4 cup water and a pinch of salt. Begin to heat over medium heat until the mixture melts, stirring gently occasionally.
Cook the mixture, stirring frequently, until light golden brown and boiling. Continue cooking, swirling frequently without stirring, until golden brown and caramelized. Add the pecans and continue to cook over medium heat, stirring frequently to glaze and coat the nuts fully. Continue cooking, tossing, until the mixture no longer appears liquid and the nuts become more difficult to stir, 3 to 5 minutes. Remove from the heat, and stir in the cream and vanilla, stirring well to combine.
Pour onto a parchment paper-lined baking sheet to cool completely, 10 to 15 minutes, then coarsely chop.
Finish the rice pudding: When the rice pudding has reached the appropriate doneness, turn the heat to low, and stir in the cream, butter, and vanilla. Cook until the mixture is heated through, 2 to 3 minutes.
Serve the rice pudding warm or pour it into a heatproof bowl, cover directly with plastic wrap and refrigerate until ready to serve cold. Serve dusted with cinnamon and topped with the coarsely chopped candied nuts.