1. Mash the miso paste with some of the demerara syrup in the bottom of a cocktail shaker until the miso paste is completely softened and dissolved in the syrup. Add the rest of the syrup.
2. Add the Scotch and lemon juice to the shaker. Fill halfway with ice, cover, and shake for 15 seconds.
3. Double strain into a chilled coupe glass. Express the lemon twist over the glass, skin side down, and drop the twist into the glass.