Brew Black Tea (4 bag) in Water (4 cup), allow it to steep for 10 minutes.
While the black tea is steeping, begin making simple syrup. Add Granulated Sugar (1/2 cup), Water (1 1/2 cup), and 4-5 slices of Grapefruit (1) to a saucepan on medium stirring periodically.
Once the sugar has dissolved, remove it from heat and transport it into a heat-resistant container. Cool both the simple syrup and black tea in the fridge for 15 minutes.
Once both have cooled, make your drink! Add Bourbon (1 fluid ounce), 2 oz of cold black tea, and 2 oz of simple syrup. If this is not sweet enough for you, add another ounce of simple syrup. Stir, then fill the glass to the rim with Ice (to taste).
Optionally, add 1/2 oz of grapefruit juice to the drink to add a little tartness and garnish with Fresh Rosemary (to taste) and/or grapefruit slices.