Make pastry: Combine flour and baking powder. Place in mound on board and make a well in center. Add eggs and water to well and, using fingertips, gradually combine with flour to form a firm dough. Knead well and let rest for 30 minutes, covered by a bowl.
Mix together mutton, 1 1/2 cups onion and parsley. Season generously with salt and pepper. Add dill and thoroughly combine.
Roll out pastry until very thin. Cut into 3-inch squares. Paint with egg white. Place 1 tablespoon meat mixture in middle of pastry square. Bring corners of square to center and pinch together to seal.
Gently fry remaining finely chopped onion with clarified butter in saucepan. Add stock and then pastry bundles. Bring to a boil, cover, and simmer 35 minutes. Remove mantays with slotted spoon and divide between 8 individual serving bowls.
Add sour cream to chicken stock and combine well, but do not let boil. To serve, pour over mantays while hot.