In a mixing glass or cocktail shaker, add the blackberries, triple sec, and lemon juice. Muddle well.
Add the gin and plum bitters, then fill with ice.
Strain into a chilled cocktail glass.
Garnish with lemon twist.
Serve and enjoy!
For the best drink, try to use fresh blackberries, particularly when they are at their peak.
You'll want to match the quality of your triple sec to the gin. A popular top-shelf option is Cointreau, though there are others available that make excellent drinks. Quite often, the least expensive bottles are very syrup-like and will throw the drink out of balance.
The average lemon will yield 1 3/4 ounces of juice, so one fruit will be enough for a couple of drinks.
Before cutting the lemon to juice it, cut the lemon twist from the peel using a paring or channel knife.
Fee Brothers makes plum bitters and it may be the only commercially available option in this particular flavor.
This recipe is courtesy of Brockmans and its fruit profile does make it a perfect fit. You can, however, make an excellent drink with other gins. Do some experiments and taste the difference between this newer style of gin and more traditional dry gins. It's quite fascinating.
Try this recipe with other berries. Blueberries are the other natural complement to Brockmans, though raspberries would be a nice contrast.