Preheat oven to 350° F and line muffin tin with paper baking cups.
In the bowl of a stand mixer, or using electric beaters, cream together butter and sugar. Add eggs, vanilla, and apple cider and mix until fully incorporated.
Add flour, baking powder, cinnamon, and salt and mix until just combined.
Using a muffin scoop, or just a spoon, scoop mixture into prepared muffin tin, filling each 2/3 full.
Bake at 350° F for 18-20 minutes or until toothpick inserted in center comes out clean. Let cool completely.
Frosting
In the bowl of a stand mixer, or with electric mixer, whip together butter, brown sugar, cinnamon, and vanilla until fluffy.
Slowly add powdered sugar 1 cup at a time and mix until fully incorporated.
Transfer to piping bag, or baggie with edge cut off, and frost cupcakes.