There are tons of "correct" ways to make it, but from scouting the internet...this recipe seems to be the closet to the one we had in Madison.
2oz Burbon whiskey
3 dashes of Angostura bitters
1 tsp sugar
Splash of soda water
1 orange slice
Place sugar inside the glass, wet down with 3 dashes of bitters, add splash of soda water and swirl around or mix till sugar is desolved.
Add the fruit and muddle with the back of a spoon.
Add whiskey and ice, stir up and enjoy!
Now all we need are some cheese curds!