Old-fashioned. Take a tumbler, put in about teaspoon of sugar, add 2-3 dashes of Angostura bitters and just enough water to fully dissolve the sugar. Muddle the sugar with a flat-bottomed spoon until there are no visible crystals left. If necessary, add a little bit more water. Next, take about of 3-4 square inches of orange zest, the orange part of the peel, with as little of the albedo (white part) as possible, this can be done with a knife, but a potato peeler is easier. A dedicated zester is even better, but most people get by without one. Muddle the zest in the tumbler until an orange aroma suffuses the glass. Next, fill with ice and add 1.5 to 2 ounces of good bourbon. I prefer Four Roses. Top with an orange slice speared to a maraschino cherry and serve. Some people like a lemon twist on the rim, but that's more garnish than I want to deal with.