In a mixing bowl, cream the butter and shortening; gradually add sugar.
Add egg, milk and vanilla extract.
Combine dry ingredients; gradually add to creamed mixture. Mix well. Cover
and refrigerate for at least 2 hours.
Meanwhile, make Cherry Filling.
Roll out dough on a lightly floured surface to 1/8-inch thickness; cut with
a 2 1/2-inch heart-shaped cookie cutter dipped in flour. Place half of the cookies
on greased baking sheets; spoon 1/2 teaspoon filling in the center of each.
Use a 1 1/2-inch heart-shaped cutter to cut small hearts out of the other half
of the cookies. (Bake small heart cutouts separately.) Place the remaining hearts
over filled cookies; press edges together gently. Fill centers with additional
filling if needed. Sprinkle with sugar.
Bake at 375 degrees F for 8 to 10 minutes or until lightly browned. Cool
on wire racks.
Cherry Filling: Combine sugar and cornstarch in a small saucepan. Add juices,
cherries and butter. Bring to a boil; boil and stir for 1 minutes.