First, if you need simple syrup, prepare it by placing equal amounts of water and sugar in a small saucepan over a gentle flame. Stir until the sugar completely dissolves, then set aside to cool.
Grab a cocktail shaker and fill it halfway with ice cubes. The ice will chill and blend the ingredients beautifully.
Add the bourbon, fresh lemon juice, cranberry juice, and simple syrup into the shaker filled with ice.
Secure the shaker lid tightly and shake the mixture vigorously for about 15-20 seconds to ensure everything is well combined and nicely chilled.
After shaking, strain the mixture into a rocks glass filled with fresh ice or pour it into a chilled coupe glass, depending on your choice.
Garnish the drink with a few fresh cranberries and a slice of lemon on the side for a festive touch. Your cranberry bourbon sour is now ready to be enjoyed!