1/4 cup brown sugar (packed)
1/4 cup unbleached all-purpose flour
1 teaspoon ground cinnamon
1/4 cup butter (cut into 4 pieces)
1/4 cup chopped walnuts or pecans
2 cups unbleached all-purpose flour
1 cup Sugar
1 tablespoon baking powder
1/2 teaspoon salt
1 teaspoon baking soda
1 teaspoon ground cinnamon
2 eggs (at room temperature)
1 cup nonfat plain yogurt or buttermilk
1/2 cup vegetable oil or melted unsalted butter
1 cup diced, peeled apple (1/4-inch dice)