To make simple syrup, combine 1 cup sugar + 1 cup water and bring to a boil. Remove from heat and let cool completely. Can keep in airtight container for a few weeks and reuse!
In a blender, blend apple juice, blackberries, lemon juice, and simple syrup for 10 seconds. Strain through a strainer.
Add juice blend to a cocktail shaker and add bourbon. Shake 20 times.
Shave a lemon peel using a peeler (making sure to just shave the yellow, not deep into the bitter white area). Wipe the rim of the glass with the lemon peel and then drop it into the glass.
Strain the chilled bourbon mixture into the glass and serve. You can serve it straight up chilled or over a large ice cube.
Want to make a large batch? Repeat in larger quantities and strain juice mixture into a large pitcher or beverage dispenser. Add bourbon and lemon juice and stir well. Add fresh lemon slices and keep in refrigerator until ready to serve. Serve over ice and add a lemon peel to garnish.