Preheat oven to 350°. In a large bowl, cream butter and sugar substitute until light and fluffy, 5-7 minutes. Beat in eggs and extract. Combine flour, baking soda and salt; mix into creamed mixture. Stir in chocolate chips. , Drop by tablespoonfuls 2 in. apart onto ungreased baking sheets. Bake at 350° for 9-10 minutes or until golden brown around the edges. Remove to wire racks to cool.