Combine sweet potatoes, liquid or water, honey and butter; heat to very warm, between 120° to 130°F. Set aside. Combine whole wheat flour, 1 cup bread flour, salt, nutmeg and undissolved yeast in a large mixer bowl. Add warm liquids and beat 2 minutes. Add egg. Beat 2 minutes more. Turn dough out on lightly floured surface and knead 8 to 10 minutes, until smooth and elastic. Cover and let rest 10 minutes.
2
Shape dough into a loaf and place in greased 9 x 5-inch loaf pan. Cover loosely with greased plastic wrap; let rise in a warm draft-free area for 30 to 45 minutes until double.
Bake in a preheated 350°F oven for 35 to 40 minutes. Cover with foil after 25 minutes to prevent over-browning. Remove from pan and brush with melted butter if desired.