Line a baking sheet with parchment paper; set aside.
Place pecans in a medium saucepan. Add maple syrup and cook, stirring often, over low heat.
Cook for 5 to 6 minutes until the syrup begins to crystallize and coat the pecans.
Sprinkle with optional flaky sea salt, if using.
Spread pecans onto the prepared baking sheet and set aside until ready to use.
In a medium pot whisk to combine milk, ½ cup heavy cream, ¼ cup granulated sugar, vanilla, 2 teaspoons chai spice, and salt.
Bring to a very light simmer over medium heat, whisking occasionally.
In a small bowl combine egg yolks, remaining ¼ cup sugar, and cornstarch
Whisk until smooth.
Slowly whisk hot milk mixture into egg yolks until at least half the liquid has been added.
Pour egg yolk mixture into the pot with any remaining milk mixture, and whisk over low heat until thickened, and the pudding just begins to bubble. Remove from heat.
Add butter and whisk to combine.
Pour evenly into heatproof glasses or ramekins.
If not serving warm, place plastic wrap directly on the surface of the pudding and refrigerate at least four hours, or overnight.
Before serving, whip remaining ½ cup heavy cream with confectioners' sugar to medium peaks.
Garnish each pudding with a sprinkle of remaining chai spice, pecans, and a dollop of whipped cream.