1. In bowl of stand mixer fitted with dough hook attachment, mix whole wheat flour, all-purpose flour and bread booster on low speed. Stir in sugar, yeast and salt. Beat in warm water on medium-low speed, scraping down side of bowl occasionally, for 2 to 3 minutes or until ball of dough starts to form and pulls away from side of bowl.
2. Transfer dough to lightly floured work surface; divide dough in half. Knead each half for 8 to 10 minutes or until smooth and elastic, and dough springs back when lightly pressed with 2 fingers. Cover with tea towel; let stand for 15 minutes.
3. Pat each half of dough into 6- x 8-inch (15 x 20 cm) rectangle. Fold up like a business letter, folding one short side into center of dough, then folding remaining short side over top. Using heel of your hand, press open edge closed. Gently pat and roll dough into 12-inch (30 cm) long log. Place seam side down on parchment paper–lined baking sheet. Cover and let stand for about 1 hour or until doubled in size.
4. Preheat oven to 425?F (220?C). Brush loaf with warm water; bake for 5 minutes. Reduce temperature to 400?F (200?C). Bake for 20 to 25 minutes or until golden brown and instant-read thermometer inserted into center of loaf registers 190?F (88?C). Let cool completely on rack before slicing.

Tip: Alternatively, fit each shaped loaf into greased 9- x 5-inch (23 x 13 cm) loaf pan. Let stand for about 1 hour, then bake as for free-form loaves. Let cool in pans for 5 minutes; turn out onto rack. Let cool completely.