In a cocktail shaker filled with ice cubes, add gin, lemon juice and simple syrup. Shake well.
Strain into a rocks glass filled with crushed ice. Top with crème de mure: It will sink to the bottom of the drink to create the gradient look.
Garnish with a lemon slice and a blackberry.
Notes
Gin substitute: You can change the spirit in this cocktail if you want! Make a bourbon bramble or vodka bramble. Rum would also be tasty.Crème de mûre: This is a blackberry-flavored liqueur. You can also use crème de cassis (blackcurrant) or Chambord (raspberry).Non-alcoholic Bramble: It's easy to make a non-alcoholic version. Use a non-alcoholic spirit such as Seedlip Garden 108 in place of the gin. Instead of crème de mûre, you can use homemade blackberry syrup.