Step 1

Whisk together all-purpose flour, whole-wheat flour, baking powder, and salt in a medium bowl.

Step 2

Beat 1/2 cup butter and granulated sugar in a large mixing bowl with an electric mixer on high speed until light and fluffy. Add 1 egg and 1 teaspoon vanilla. Beat until smooth. With the mixer on low speed, gradually add 1½ cups of the flour mixture, beating just until combined. Place the dough on a sheet of plastic wrap and form into a 10-inch log. Wrap and refrigerate.

Step 3

Wipe out the mixing bowl. Beat the remaining 1/2 cup butter and brown sugar with the mixer on high speed until light and fluffy. Add the remaining egg and 1 teaspoon vanilla. Beat until smooth. With the mixer on low speed, gradually add the remaining flour mixture and cinnamon, mixing until just combined. Place the dough on a sheet of plastic wrap and form into a 10-inch log. Wrap and refrigerate for 30 minutes.

Step 4

When the doughs are chilled, divide each log in half lengthwise. Working with 1 piece of vanilla dough and 1 piece of cinnamon dough, roll each into a long rope, about ½ inch thick. Place the ropes side-by-side, gently pressing the 2 doughs together. Fold in half, then twist once or twice and roll again into another log, about 1½ inches thick. Place pecans on a clean surface and roll the log in the nuts, pressing gently to adhere. Rewrap in plastic wrap and place in freezer. Repeat with the remaining dough and pecans. Freeze until the dough is firm, about 1 hour.

Step 5

Position racks in upper and lower thirds of oven; preheat to 350°F. Line 2 baking sheets with parchment paper.

Step 6

Working with 1 log of dough at a time, unwrap and slice into 1/4-inch-thick rounds, turning the dough after each slice and shaping the cookies, if necessary, to retain their shape. Bake until lightly browned, 10 to 12 minutes. Transfer the cookies to a wire rack to cool completely.