While bartenders in other cities have complicated the Sazerac by using a combination of spirits [us included - Difford's Sazerac recipe], in New Orleans...
I have found that if I use a measure of caster (superfine) sugar - a heaping teaspoon in the case of a Sazerac - add an equal measure of water plus the bitters and stir thoroughly, the sugar ends up dissolving completely without the hassle of making sugar syrup.