This came up in MixMO as an entry from Backyard Bartender which intrigued me, especially as I still have lavender flowers.
The Fine Art of Mixing Drinks and decided to stick to a more standard old-fashioned. I'd used up all my Gomme making Jellies so I had to do it the hard way
First put 1//2 a barspoon of sugar in the bottom of your glass add 2 dashes of bitters an Ice cube & a lavender flower head. Stir gently to start dissolving the sugar. After a couple of minutes add 5ml of St Germain (Elderflower liqueur). Keep stirring gently, you want to dissolve the sugar but not break up the lavender. Add 10ml of bourbon and keep stirring. Once all the sugar has dissolved (5-10 minutes) add 35ml of bourbon and a second ice cube, stir for another 10-15 seconds and then enjoy.
You should end up with a very well balanced drink in which the lavender & elderflower florals combine and act quite nicely with the bourbon, giving a smooth drink with a bright aftertaste. It is always a bit of hassle to make an old fashioned from scratch, but this one is worth a go.