Whisk together flour and salt in a bowl. Beat together butter and cream cheese in a large bowl with an electric mixer until combined well.
Add flour mixture and stir with a wooden spoon until a soft dough forms. Gather dough into a ball and wrap in plastic wrap, then flatten (in wrap) into a roughly 7- by 5-inch rectangle. Chill until firm, 8 to 24 hours.
Put oven rack in middle position and preheat oven to 350°F. Line bottom of a 1- to 1 1/2-inch-deep large shallow baking pan with parchment paper.
Cut dough into 4 pieces. Chill 3 pieces, wrapped in plastic wrap, and roll out remaining piece into a 12- by 8-inch rectangle on a well-floured surface with a floured rolling pin.
Transfer dough to a sheet of parchment, then transfer to a tray and chill while rolling out remaining dough in same manner, transferring each to another sheet of parchment and stacking on tray.
Whisk 1/2 cup sugar with cinnamon.
Arrange 1 dough rectangle on work surface with a long side nearest you.
Spread 1/4 cup preserves evenly over dough with offset spatula.
Sprinkle 1/4 cup raisins and a rounded 1/4 cup walnuts over jam, then sprinkle with 2 tablespoons cinnamon sugar.
Using parchment as an aid, roll up dough tightly into a log.
Place, seam side down, in lined baking pan, then pinch ends closed and tuck underneath. Make 3 more logs in same manner and arrange 1 inch apart in pan.
Brush logs with milk and sprinkle each with 1 teaspoon of remaining granulated sugar. With a sharp large knife, make 3/4-inch-deep cuts crosswise in dough (not all the way through) at 1-inch intervals. (If dough is too soft to cut, chill until firmer, 20 to 30 minutes.)
Bake until golden, 45 to 50 minutes. Cool to warm in pan on a rack, about 30 minutes, then transfer logs to a cutting board and slice cookies all the way through.
