Muddle a sugar cube, a few dashes of bitters, a splash of club soda, and a twist of lemon peel and orange peel together in a highball glass until the sugar is dissolved.
(Many Old Fashioned recipes call for the peels as garnish at the end, but I prefer to muddle with the sugar for a little more flavor).
Fill the glass with crushed ice and add rye whiskey to nearly the top of the glass. Add another splash of club soda and stir. Garnish with a maraschino cherry, if you so desire.
Now, drink it like an old man.