In a large bowl, cut butter into flour until mixture resembles coarse crumbs. Stir in sour cream and salt. Shape the dough into a ball; cover and refrigerate overnight.
For filling, combine bread crumbs and butter. Add apples, sugar, raisins, pecans and cinnamon; set aside.
Preheat oven to 350°. Divide dough into thirds; turn onto a floured surface. Roll each into a 15x12-in. rectangle. Spoon filling evenly onto dough; spread to within 1 in. of edges. Roll up from a long side; pinch seams and ends to seal.
Carefully place each loaf seam side down on an ungreased baking sheet. Bake 55-60 minutes or until lightly browned. Cool completely on wire racks. Dust with confectioners' sugar if desired.