Prepare the Pan: Butter a 9"x13" pan and line with parchment paper, leaving an overhang on the sides for easy removal. Butter the parchment and set the pan aside.
Reduce the Apple Cider: In a medium saucepan over medium heat, simmer the apple cider until it reduces to about 1 cup, which will take 30 minutes to 1 hour. Keep a close eye on it during the last 15 minutes to prevent burning. The cider should become thick and syrupy when ready.
Prepare the Cream Mixture: In another pot, combine the heavy cream and 1/2 cup of butter. Heat over medium heat until the butter melts and the mixture begins to simmer.
Make the Caramel Base: In a large, heavy-bottomed pot, add the sugar, reduced apple cider, corn syrup, water, and salt. Attach a candy thermometer to the side of the pot. Without stirring, bring the mixture to a simmer over medium-high heat until the sugar dissolves and starts to caramelize. Stir gently only as needed to dissolve any crystals on the sides.
Combine Mixtures: Slowly add the heated cream mixture to the caramel base, stirring continuously. Continue cooking over medium heat, stirring occasionally, until the caramel reaches 250°F.
Add Spices: Once the mixture reaches temperature, stir in the vanilla extract, cinnamon, allspice, ginger, and nutmeg.
Pour and Set: Carefully pour the caramel into the prepared pan, spreading it evenly with a spatula if necessary.
Cool and Slice: Allow the caramel to cool to room temperature, then cover and refrigerate until completely set and cold.
Cut and Wrap: Once firm, lift the caramel out of the pan using the parchment overhang. Slice the caramel into 1-inch wide strips, then cut each strip into bite-sized pieces. Wrap each caramel in wax or parchment paper.