Mushroom Tarts

2/3 cup of butter
2 1/2 cups of flour
1/2 teaspoon of salt
1/3 cup of sour cream
1 egg, slightly beaten

Cut the butter into flour and salt. Add sour cream and egg. Cut with pastry blender until well blended. Using 1 teaspoon dough, press into bottom and side of tart muffin pans. Bake at 400ºF. for 12 - 15 minutes, or until golden. remove from tart pan and cool.