Simmer apple cider until reduced to 1/2 cup. Let cool. Preheat oven to 350°F. Whisk dry ingredients together. Cream butter and brown sugar until smooth. Add eggs and vanilla. Stir in reduced cider. Fold in dry ingredients. Pour into greased loaf pan. Bake 45–50 minutes until set. Cool slightly, then coat with cinnamon sugar if desired.
Notes
Do not skip cider reduction. It creates strong apple flavor.