In a bowl and using an electric mixer on medium speed, beat shortening, peanut butter, brown sugar and 1/2 of sugar until creamy.
Beat in egg, milk and vanilla.
In another bowl, combine flour, baking soda, and salt. Gradually add to creamed mixture, beating on low speed until blended.
Shape dough into 1-inch balls and roll in the remaining 1/4 cup of sugar. Arrange 2 inches apart on an ungreased baking sheet.
Bake in a 375 F oven for about 10 to 12 minutes or until golden brown.
Remove from oven and immediately top each cookie with one chocolate piece, pressing down firmly until cookie cracks around edge.
Transfer cookies to wire rack to cool completely.