Cranberry Lemon Sandwiches

In a large bowl, cream the butter, shortening and sugars until light and fluffy.

Add eggs, one at a time, beating well after each addition. Beat in vanilla.

Combine the flour, cream of tartar, lemon peel and salt; gradually add to the creamed mixture and mix well. Stir in cranberries. Cover and refrigerate for 2 hours or until easy to handle.

Roll into 1-in. balls.

Place 2 in. apart on ungreased baking sheets. Flatten with a glass dipped in sugar.

Bake at 350° for 12-14 minutes or until edges are lightly browned.

Remove to wire racks to cool.

In a small bowl, combine the filling ingredients; beat until smooth.

Spread on the bottoms of half of the cookies; top with remaining cookies.