1 fluid ounce spiced rum (such as Sailor Jerry®)
1 fluid ounce butterscotch schnapps
1/2 teaspoon imitation butter flavoring
1 (12 fluid ounce) can or bottle cream soda
1 small scoop vanilla ice cream (optional)
Stir rum and butterscotch schnapps together in a frosted 14-ounce mug.
Pour butter flavoring into the cream soda, then turn cream soda over to pour quickly into the chilled mug. Gently drop the ice cream into the soda mixture.