Preheat oven to 350 degrees F. Lightly grease a cookie sheet; set aside. In a small microwave-safe bowl, combine shortening and chocolate. Microwave on 100 percent power (high) for 30 to 60 seconds or until shortening is just melted and chocolate is softened; stir until smooth. Set aside.

In a large bowl, beat egg and brown sugar with an electric mixer on medium speed until light and fluffy. Add vanilla and melted chocolate mixture; beat well.

In a medium bowl, stir together flour, baking soda, and salt. Alternately beat flour mixture and milk into chocolate mixture just until combined. If desired, stir in nuts. Drop dough by rounded teaspoons 2 inches apart on prepared cookie sheet. Bake in the preheated oven about 10 minutes or until edges are firm. Transfer cookies to a wire rack; let cool.

If desired, spread about 1 tablespoon Creamy Filling on the flat sides of half of the cookies. Top with the remaining cookies, flat sides down. Makes 44 cookies or 22 sandwich cookies.

Creamy Filling:In a medium bowl, combine 2/3 cup shortening, 1/2 cup granulated sugar, 1/3 cup milk, 1 tablespoon water, 1 teaspoon vanilla, and 1/4 teaspoon salt. Beat with an electric mixer on medium speed for 5 to 7 minutes or until light and fluffy. Add 1/2 cup powdered sugar and beat for 5 minutes, scraping bowl occasionally. Makes about 1 1/2 cups.

Tip:You can also frost these cookies with purchased or homemade vanilla or chocolate frosting. Or for ice cream sandwiches, use softened ice cream in place of the Creamy Filling, individually wrap sandwiches with plastic wrap, and freeze for 2 hours or until firm.

Layer filled or unfilled cookies between sheets of waxed paper in an airtight container; cover. Store at room temperature for up to 3 days or freeze for up to 3 months. To serve, thaw cookies if frozen. If desired, prepare filling as directed and assemble sandwich cookies as directed in Step 4.