In a large mixing bowl, cream butter and sugar.
Add egg;mix well.
Beat in molasses.
Combine flour, baking soda, salt, cinnamon and ginger; add to creamed mixture and mix well. (The dough will be very stiff)
Cover and chill several hours or overnight.
On a lightly floured surface roll dough to 1/8 inch thickness, cut into 2 1/4 inch to 2 1/2 inch circles.
Place 1/2 tspn preserves on half of circles.
Top with remaining circles pinch edges together to seal.
Bake at 350º for 10 minutes.
Frosting: Combine confectioners' sugar, water and vanilla extract.
Allow cookies to cool and frost.