Preheat oven to 375 degrees F. In a large bowl, beat butter with an electric mixer on medium to high speed for 30 seconds. Add sugar, baking powder, and salt; beat until combined, scraping side of bowl occasionally. Beat in eggs and vanilla until combined. Beat in as much of the flour as you can with the mixer. Using a wooden spoon, stir in any remaining flour.

Divide dough in half; place each half in a bowl. Into half of the dough, stir the melted chocolate and 1/2 cup of the nuts. Into the other half of the dough, stir the orange peel and the remaining 1/2 cup nuts.

Divide each half of the dough into 3 portions. With lightly floured hands, shape each dough portion into a rope about 14 inches long. Place a rope of each color side by side on an ungreased cookie sheet. Twist ropes around each other several times. Flatten slightly to a 2 inch width. Repeat with the other ropes to make 3 twists total, placing twists about 4 inches apart on the cookie sheet.

Bake about 25 minutes or until lightly browned. Cool on cookie sheet about 1 hour or until completely cool.

Preheat oven to 325 degrees F. Transfer baked twists to a cutting board. Cut into 1/2-inch-thick slices. Place slices on the same cookie sheet. Bake for 10 minutes. Turn slices over; bake for 10 to 15 minutes more or until dry and crisp. Transfer cookies to a wire rack; cool. Makes about 70 cookies.

Nutrition facts are based on one cookie.