In large bowl, combine flour, cinnamon and baking powder.
In large bowl, beat butter and sugar with electric mixer until light and fluffy. Add egg, milk and vanilla; mix well. Gradually add flour mixture to butter mixture, mixing until dough is smooth. Do not chill. Place dough into cookie press and press cookies onto ungreased cookie sheet.
Bake 10-12 minutes or until lightly browned around edges. Cool 2 minutes on pan on cooling grid. Remove from cookie sheet; cool completely on grid.
Spread about 1 teaspoon dulce de leche on back of half the cookies. Sandwich with remaining cookies.