In small bowl, dissolve yeast and 1 teaspoon sugar in warm water. Let stand 5 minutes.
In large bowl, combine flour, remaining sugar and salt; mix well. With pastry blender, cut in butter until the consistency of cornmeal. Add dissolved yeast and egg yolks to flour mixture; mix lightly with fork. Shape prepared dough into a ball. Cover with plastic wrap; refrigerate for 2 hours. (This is a rich dough; it rises very little.)
Prepare filling: In a mixing bowl, beat cream cheese, sugar and egg yolk until smooth; set aside.
Prepare glaze: In a small bowl, combine glaze ingredients; blend until smooth.
Divide dough into 2 equal parts. On lightly floured surface, roll each half into a 15x10-inch rectangle. Roll rectangle onto rolling pin to transfer to a greased 15x10-inch jelly roll pan. Spread prepared filling over dough. Top evenly with blueberries (optional), pressing gently into the filling. Carefully place remaining rectangle over filling. Topping: Brush top of dough with slightly beaten egg white. Sprinkle pecans evenly over top of dough. Cover; let rise in warm place about 1 hour.
Preheat oven to 350°F.
Bake for 20-25 minutes. Drizzle glaze over warm coffee cake. When cool, cut into squares or bars. Store in refrigerator. Reheat in warm oven.