Preheat oven to 375 degrees. Lightly flour large baking sheet. Whisk first 5 ingredients in large bowl to blend well. Add butter and rub in with fingertips until mixture resembles coarse meal. Mix in toasted, chopped walnuts. Whisk buttermilk, egg and molasses in small bowl to blend.
Gradually add buttermilk mixture to flour mixture, stirring until medium-firm dough forms. Turn dough out onto lightly floured surface. Knead until dough comes together, about 6 turns. Flatten dough into disk. Cut into 6 wedges. Shape each wedge into a ball. Flatten each ball to 3-inch round. Place on prepared sheet, spacing evenly apart.
Bake breads until golden and tester inserted into center comes out clean, about 30 minutes. Transfer to rack. Serve warm or at room temperature. Makes 6 mini loaves.