First make the Homemade Vanilla Bean Simple Syrup. Cut the vanilla bean in half, remove the seeds and set aside. Add 1 cup water and 1 cup sugar to a small saucepan. Bring to a boil. Add in vanilla bean seeds and boil on low for 10 minutes. Remove from heat and set aside. [Optional: strain syrup mixture in cheesecloth to remove any vanilla bean clumps]. Pour into a glass container and store in the fridge up to a week.
To make the espresso martini, add all ingredients into a cocktail shaker full of ice. Shake vigorously. Pour into a martini glass and garnish with shakeable chocolate topping. Enjoy!