To make pomegranate molasses, in 2-quart heavy saucepan, heat pomegranate juice, jam, sugar, and 3/4 teaspoon of the lemon juice over medium heat, stirring constantly, until jam is melted and sugar is dissolved. Reduce heat to low. Simmer 30 to 40 minutes, stirring occasionally or until mixture is thickened and measures about 2/3 cup. Set aside.
Meanwhile, in small bowl, combine mayonnaise, sour cream, remaining 1 teaspoon lemon juice and 3/4 teaspoon of the rosemary; mix well. Cover; refrigerate.
Heat oven to 350°F. In small bowl, stir together cumin, 1 teaspoon of the rosemary, white pepper and salt. In large bowl, combine turkey, cumin mixture, feta and onion; mix well. Shape into 5 (4-inch) patties. Cover; refrigerate.
Separate dough into 5 biscuits; place on ungreased cookie sheet. Sprinkle tops of biscuits with remaining 1/4 teaspoon rosemary; lightly press into dough.
Bake 10 to 13 minutes or until golden brown.
Set oven to broil. Broil patties 6 inches from heat 4 minutes. Turn patties; broil an additional 6 to 9 minutes or until thermometer inserted in center of patties reads 165°F. Let stand 2 minutes.
Split biscuits; spread mayonnaise mixture on split sides of each biscuit. Fill biscuits with patties and lettuce leaves. Divide pomegranate molasses evenly among 5 ramekins. Serve burgers with pomegranate molasses.