Preheat oven to 350 degrees. Spray a 6 well donut pan with non-stick spray.
In a saucepan, bring apple cider to a boil for about 15-20 minutes to reduce to ¾ cup. Cool to room temperature or refrigerate to cold.
In a mixing bowl or stand mixer, add eggs, oil, and brown sugar. Mix until combined. Add reduced apple cider and buttermilk and combine. Add dry ingredients and mix until everything is incorporated. Using a piping bag, pipe the donut cavities 2/3 full and bake 18-20 minutes.
Cool until you can safely remove doughnuts from the pan. Top with a spoonful of caramel sauce and chopped pecans if desired.
CARAMEL SAUCE: In a small saucepan over low-medium heat, add condensed milk, butter, brown sugar, and corn syrup. Whisk until the sugar is melted for about 5 minutes. Do not overcook. Turn off the heat and add vanilla and salt. Cool completely before serving.
Recipe by our friend Monique @Peaches2Peaches