- 1 serving Baking spray with flour
- ⅔ cup granulated sugar
- ½ cup plain whole-milk Greek yogurt
- 2 large eggs large eggs
- ⅔ cup unsweetened applesauce
- 1 teaspoon vanilla extract
- 7 tablespoons unsalted butter, melted, divided
- 1 cup all-purpose flour, plus 1 tablespoon, divided
- ¾ cup whole-wheat flour
- 1 teaspoon baking soda
- 1 teaspoon apple pie spice
- ½ teaspoon salt
- 1 large Granny Smith apple, diced (1/4-inch; about 1 cup)
- ½ cup coarsely chopped walnuts
- 3 tablespoons light brown sugar
- ¼ teaspoon ground cinnamon
1Preheat oven to 350 degrees F. Coat a 9-by-5-inch loaf pan with baking spray.
2Stir granulated sugar, yogurt and eggs together in a large bowl until well combined. Add applesauce, vanilla and 6 tablespoons melted butter; stir well to combine and set aside.
3Whisk 1 cup all-purpose flour, whole-wheat flour, baking soda, apple pie spice and salt in a medium bowl. Add chopped apple and stir until the pieces are evenly coated. Add the flour-apple mixture to the egg mixture; stir until just combined. Spoon into the prepared loaf pan.
4Combine walnuts, brown sugar, cinnamon and the remaining 1 tablespoon each melted butter and all-purpose flour in a small bowl. Sprinkle evenly on the batter in the pan.
5Bake until a wooden pick inserted in the center of the loaf comes out clean, 55 to 60 minutes. Cool in the pan for 10 minutes. Gently turn out onto a wire rack; let cool completely, about 1 hour.