1Heat oven to 325ºF. Grease bottom only of 8x4-inch loaf pan with shortening or cooking spray; lightly flour.
2In large bowl, beat sugar, butter, yogurt and eggs with electric mixer on medium speed until light and fluffy. On low speed, beat in flour, cinnamon, baking powder, vanilla and salt. Stir in apples and walnuts. Spoon batter into pan. Sprinkle crushed granola bar evenly over top of batter, pressing lightly into batter.
3Bake 1 hour 5 minutes to 1 hour 10 minutes or until toothpick inserted in center comes out clean. Cool 5 minutes. Loosen sides of loaf from pan; remove from pan to cooling rack. Cool completely, about 1 hour. Use serrated knife to cut loaf into 16 slices. Wrap tightly and store in refrigerator.