1. In a large bowl, combine turkey, blueberries, ginger, lemongrass and black pepper; mix well.
2. Form mixture into 4 patties.
3. Brush soy sauce on both sides of burgers.
4. In an oiled skillet over medium-high heat, grill patties until cooked thoroughly, about 4 minutes each side.
5. Serve on buns with lettuce, sliced red onion and blueberry ketchup.

* Peel away woody outer layer from the bottom portion of the lemongrass stalk; mince inner flesh.

1. In a medium saucepan over medium heat, combine blueberries, onion, vinegar, sugar, ginger and salt.
2. Bring to a simmer; cook about 15-20 minutes, stirring frequently.
3. Remove from heat and allow to cool.
4. Remove to blender or food processor; whirl until smooth.
5. Refrigerate until ready to use.