Beat first 4 ingredients at medium speed with an electric mixer 2 minutes or until well blended. Add egg substitute, beating until well blended.
Combine flour and next 3 ingredients; add to butter mixture, beating at low speed just until blended. Stir in chocolate and, if desired, nuts.
Divide dough in half; shape each portion into a 10- x 2-inch log on a lightly greased baking sheet.
Bake at 350° for 23 to 25 minutes or until firm and lightly browned. Cool on baking sheet 5 minutes. Remove to wire racks to cool completely.
Cut each log diagonally into 1/2-inch slices with a serrated knife, using a gentle sawing motion. Place slices on ungreased baking sheets.
Bake at 350° for 7 to 9 minutes; turn cookies over, and bake 7 to 9 more minutes or until cookies are browned. Remove cookies to wire racks to cool completely.
Note: For testing purposes only, we used Equal Sugar Lite, Café Bustelo Instant Coffee (Espresso), and Ghirardelli Dark Chocolate.
Per cookie (without nuts): Calories 94 (35% from fat); Fat 3.7g (sat 2.1g, mono 0.6g, poly 0.2g); Protein 1.6g; Carb 14g; Fiber 0.5g; Chol 6mg; Iron 0.8mg; Sodium 57mg; Calc 21mg.