1. Heat grill to medium-high heat. Heat 1 tablespoon of the oil in a medium saucepan over medium heat. Add onion and cook 4 to 5 minutes, until softened. Add garlic and 1 teaspoon of the rosemary. Cook 1 minute. Carefully stir in bourbon and simmer 3 minutes, until almost all liquid has evaporated.
2. Stir in blueberries, sugar, vinegar, 1/2 teaspoon of the salt and the pepper flakes. Simmer, stirring occasionally, 15 minutes.
3. Meanwhile, combine remaining tablespoon oil, 2 teaspoons rosemary, 1/4 teaspoon salt and the black pepper. Brush onto both sides of the pork.
4. Separate leeks into layers. Grill leeks about 4 minutes, until soft and flat. Transfer to a platter. Grill pork 8 minutes, turning once, until internal temperature registers 145 degrees F. Let rest 5 minutes, then place over leeks and top with sauce.