01 - Preheat oven to 350°F. Grease and line a 9x5-inch loaf pan with parchment paper.
02 - In a large bowl, whisk together all-purpose flour, ground flaxseed, baking soda, baking powder, salt, ground cinnamon, and optional nutmeg.
03 - In a separate medium bowl, whisk unsweetened applesauce, oil, packed light brown sugar, eggs, and vanilla extract until well combined and smooth.
04 - Pour wet ingredients into dry mixture and stir gently until just incorporated. Avoid overmixing the batter.
05 - Fold in chopped walnuts or pecans and raisins or dried cranberries, if desired.
06 - Transfer batter into the prepared loaf pan, then smooth the top with a spatula.
07 - Bake for 45 to 55 minutes until a toothpick inserted into the center emerges clean.
08 - Allow loaf to cool in pan for 10 minutes, then remove and place onto a wire rack to cool completely before slicing.