In a bowl, whisk together flour, baking soda, baking powder, cinnamon, and nutmeg.
2. Cream Butter & Sugar
In a separate bowl, beat softened butter and brown sugar until fluffy.
Add eggs one at a time, then mix in vanilla extract.
3. Combine Wet and Dry
Gradually fold in applesauce and then the dry ingredients until just combined.
4. Add Mix-Ins
Fold in nuts and raisins, if using.
Pour batter into a greased or lined 9×13-inch baking pan.
5. Bake
Bake at 350°F (175°C) for 35–40 minutes, or until a toothpick inserted in the center comes out clean.
Let cool before glazing.
6. Optional Glaze
Whisk powdered sugar, milk, and vanilla until smooth.
Drizzle over cooled cake.
