Line a 8x8 in pan with parchment paper, and light grease. Set it aside.
Add the apple cider to a large, heavy bottomed and heat it over medium on the stove top. Bring it to a simmer and cook until it is reduced to about 1/2 cup. 4 cups Apple Cider
Add the sugar, corn syrup, butter, and salt to the large pot with the apple cider and heat it over medium on the stove top. Stir occasionally as the mixture comes to a boil. 2 cups Granulated sugar, 1/2 cups light corn syrup, 1/2 cup unsalted butter,
Once boiling, very slowly add the evaporated milk a little at a time, a couple TBS at a time, stirring constantly. It will take a few minutes to add, and you need to stir the whole time so the milk doesn't significantly lower the temperature of the mixture. 12 oz evaporated milk
Once all the milk has been added, add in a candy thermometer and continue cooking, stirring constantly until the mixture comes between 245 and 250 Fahrenheit.
Once the temperature is reached, remove from the heat and stir in the vanilla extract, salt, and cinnamon. 1 tsp vanilla extract, 1/2 tsp salt, 1/2 tsp ground cinnamon
Pour the mixture into the prepared pan, and spread out the top as needed.
Let the caramels cool for 30 minutes. Then sprinkle the top with flakey sea salt if desired. flaky sea salt
Let the caramels cool until totally set. Lift the caramels out of the pan, with the parchment paper and cut them into bite sized pieces, using a sharp knife.