Preheat the oven to 350° F. Spray a standard muffin tin with vegetable spray and set aside.
Spread ½ cup toasted walnuts on a baking sheet and bake for 8-10 minutes, or until toasted and fragrant. Set aside to cool.
In a large bowl, combine 2 cups all-purpose flour, ½ teaspoon salt, 1½ teaspoons baking powder, ½ teaspoon baking soda, 1½ teaspoons cinnamon, ½ teaspoon allspice, ½ teaspoon nutmeg and ¼ teaspoon ground ginger. Whisk to combine and set aside.
In a medium bowl, combine 1 cup applesauce, 1 large egg, ⅓ cup canola or vegetable oil, ¾ cup sugar and ¾ cup buttermilk. Whisk to combine.
Add the wet ingredients to the dry ingredients and stir until mixed and no dry bits of flour remain. Add the walnuts and stir to combine.
Fill the muffin tins with the applesauce muffin batter, about ⅔ to ¾ full. Bake for 20-25 minutes, or until a toothpick poked into the center of a muffin comes out clean.
Transfer the muffins to a wire rack to cool.
Notes
Keep the muffins at room temperature for up to 2 days; refrigerate after that.
For the best flavor and texture, let them come to room temperature after refrigerating.
Freeze in a zip-top storage bag or container for up to 3 months.
To freeze: line a baking sheet with parchment paper and freeze muffins (not touching) on the pan until solid. Transfer to a storage container or bag and store in the freezer for up to 3 months.