PINEAPPLE UPSIDE DOWN BUNDT CAKE

–½ cup butter, melted

–½ cup packed brown sugar

–1 – 20-ounce can pineapple slices, juice reserved

–1 jar maraschino cherries

–1 box yellow cake mix

–1 – 3.4-ounce box vanilla pudding mix

–3 eggs

–⅓ cup vegetable oil

–⅓ cup milk, plus more as needed