Preheat oven to 375 degrees F. In a large mixing bowl beat butter and shortening with an electric mixer on medium to high speed for 30 seconds. Add the brown sugar, granulated sugar, baking soda, and salt. Beat until mixture is combined, scraping sides of bowl occasionally. Beat in eggs and vanilla until combined. Beat in as much of the flour as you can with the mixer. Stir in any remaining flour. Stir in chocolate pieces.

Drop dough by rounded teaspoons 2 inches apart onto an ungreased cookie sheet. Bake for 8 to 9 minutes or until edges are lightly browned. Transfer to a wire rack and let cool. Makes about 60 cookies.

Prepare as above, except substitute white baking pieces for the semisweet chocolate pieces. Stir in one 3 1/2-ounce jar macadamia nuts, chopped, with the baking pieces.

Prepare as above, except press dough into an ungreased 15x10x1-inch baking pan. Bake in a 375 degree oven for 15 to 20 minutes or until golden. Cool on a wire rack. Cut into bars. Makes 48 bars.

Prepare as above, except use a 1/4-cup measure or scoop to drop mounds of dough about 4 inches apart onto an ungreased cookie sheet. If desired, flatten dough mounds to circles about 3/4-inch thick. Bake in a 375 degree oven for 10 to 12 minutes or until edges are lightly browned. Let cool on pans on wire rack for 1 minute. Transfer cookies to a wire rack and let cool. Makes about 18 cookies.