Chocolate & Orange Marbled Cookies

from: Cookies for Santa

1/2c packed brown sugar
1/2c sugar
1/2c butter
1/2c sour cream
1 egg
2 T orange juice
1 t grated orange peel
1 t vanilla
2c flour
1/2t baking soda
1/4t salt
1 oz unsweetened baking chocolate, melted

Preheat oven to 350. Combine brown sugar, sugar and butter in large mixing bowl. Beat at medium speed, scraping bowl often until creamy. Add sour cream, egg, orange juice, orange peel and vanilla. Continue beating until well mixed. Reduce mixed speed to low and add flour, baking soda and salt. Beat, scraping the bowl often until well mixed. Pour slightly cooled chocolate over batter; swirl through batter with knife for marbled effect. Drop dough by rounded teaspoonfuls two inches apart onto ungreased cookie sheet. Bake for 10-12 minutes or until lightly browned.