In a large bowl, cream the Crisco, peanut butter and sugars. Beat in eggs and vanilla, one at a time, beating well after each addition. Combine the flour, baking soda and salt; add to creamed mixture and mix well. Shape into 1-inch balls and place 2 inches apart on ungreased baking sheets. Flatten to 3/8-inch thickness with fork. Bake at 375° for 7-8 minutes or until golden. Remove to wire racks to cool. For filling, in a large bowl, beat the peanut butter, confectioners’ sugar, vanilla and enough milk to achieve spreading consistency. Spread on half of the cookies and top each with another cookie.