Combine butter and cream cheese in large bowl. Beat at
medium speed, scraping bowl often, until creamy. Add sugar,
egg, lemon peel and lemon juice; continue beating until well
mixed. Reduce speed to low; add flour, baking powder, baking
soda and salt. Beat until well mixed. Cover; refrigerate until firm
(at least 1 hour).
Heat oven to 350°F. Roll out dough, one-half at a time (keeping
remaining dough refrigerated), on well-floured surface to 1/8-
inch thickness. (Add additional flour to rolling surface as
needed.) Cut with 2 to 3-inch cookie cutters.
To assemble cookies, spread 1/4 teaspoon jam in center of 1
cookie; top with second cookie. Gently press edges of cookies
to seal. Place 2 inches apart onto ungreased cookie sheets.
Bake for 8 to 10 minutes or until edges are lightly browned. Cool
Combine powdered sugar and vanilla in small bowl. Beat at low
speed, adding enough milk for desired spreading consistency.
Frost cooled jam-filled cookies with 1/2 teaspoon each.