Step #4 In large bowl, mix flour, baking powder, salt, sugar, & baking soda.
Step #5 With pastry mixer or 2 knives, cut the butter in until mixture resembles coarse crumbs.
Step #6 Remove 1 1/4 C flour mixture to medium-size bowl.
Step #7 2.
Step #8 In small bowl, mix buttermilk & vanilla.
Step #9 In c, mix 1/4 C buttermilk mixture & the chocolate.
Step #10 add in the remaining buttermilk mixture to remaining flour mixture in large bowl & mix lightly with fork until it clings together & forms a soft dough.
Step #11 Add chocolate mixture to the reserved 1 1/4 C flour mixture in medium-size bowl and stir with fork until it forms a soft dough.
Step #12 3.
Step #13 Turn both doughs out onto lightly floured surface; divide chocolate dough into 6 pieces.
Step #14 Dot 3 chocolate pieces over surface of plain dough.
Step #15 Fold plain dough over & dot with remaining 3 pieces chocolate dough; knead 5 or 6 times to marbleize dough.
Step #16 Divide dough in half.
Step #17 With lightly floured rolling pin, roll one half of dough into a 7-inch round.
Step #18 Cut into 4 wedges.
Step #19 Repeat with remaining half of dough.
Step #20 4.
Step #21 Place scones, 1 inch apart, on greased baking sheet.
Step #22 Pierce tops with tines of fork.
Step #23 5.
Step #24 Bake scones 15 to 18 mins or until golden brown.