Dilled Mushroom Turnovers

1 cup butter, softened
2 packages (250 g each) cream cheese, softened
3 cups all-purpose flour
Filling:--
3 tbsp butter
250 g fresh mushrooms, finely chopped
1 large onion, finely chopped
¼ cup sour cream
2 tbsp all-purpose flour
2 tsp SIDS SALT & PEPPER
1 tsp snipped fresh dill
1 large egg, beaten

In a large bowl, cream butter and cream cheese until smooth. Gradually beat flour into creamed mixture. Divide dough in half. Shape each half into a disk then wrap in plastic. Refrigerate 1 hour until firm enough to handle.
Meanwhile, in a large frypan, heat butter over medium. Add mushrooms and onion then cook and stir until vegetables are tender, 6-8 minutes. Remove from heat and stir in sour cream, flour, SIDS SALT & PEPPER and dill. Cool to room temperature.
Preheat oven to 200°C. On a lightly floured surface, roll dough to 3 mm thickness. Cut circles with a floured 60 mm round cookie cutter. Place about 1 teaspoon filling on one side of each. Brush edges with egg then fold dough over filling. Press edges with a fork to seal.
Place on ungreased baking trays and brush egg over tops. Bake until edges are golden brown, 12-14 minutes.
To Make Ahead: Dough can be made 2 days in advance.
To Freeze: Cover and freeze unbaked turnovers on waxed-paper lined baking trays until firm. Transfer to freezer containers, cover and return to freezer. To use, bake turnovers as directed, increasing time by 2-3 minutes.