Bleuberry Coffeecake

I got this recipe from a large book called "Great American Baking"-there are no author credits. I bought it used from a disgruntled chef leaving the business. I have alot of blueberries for some reason and this looked appealing to me. Dough: 1 package dry active yeast 1/4 cup warm water1/4 cup sugar 1/4 cup milk, scalded and cooled 1/2 teaspoon salt 1 egg 1/4 cup butter, melted 2 to 2 1/2 cups flour Dissolve the yeast in the water, let it sit for 5 minutes until it becomes foamy, add the sugar, milk, salt, egg, and butter. Begin adding the flour 1 cup at a time, knead until smooth and elastic. I just mixed it all up in my Kitchen Aid and left it on the dough hook for about 10 minutes. Place the dough in a greased bowl, turn to coat and cover the bowl wtih a towel or plastic wrap, place in a warm place to rise until doubled-about 1 1/2 hours. Filling: 2 cups blueberries 3/4 cups sour cream-I used blueberry yogurt 1 egg 3 tablespoons brown sugar Combine the blueberries, sour cream or yogurt, and egg-reserve the brown sugar. To assemble the cake: Roll out the dough into a 13" by 10" rectangle, and place it on a greased baking sheet. Make 3" cuts at 1/2" intervals along the long sides of the rectangle of dough. Spread the blueberry-sourcream mixture down the center of the dough. Sprinkle the reserved brown sugar over the berries. Fold the short ends of the dough up over the filling. Criss cross the strips along the side up over the filling. Brush the top with egg wash and sprinkle with sanding sugar. Cover lightly and let rise for 1 hour. Bake in a preheated 375 degree oven for about 25 minutes.