Preheat your oven to 350°F (175°C). Grease and flour a 9x13 inch baking dish.
In a large mixing bowl, combine the flour, sugar, baking soda, baking powder, cinnamon, and salt. Mix well to combine.
In another bowl, whisk together the vegetable oil, applesauce, eggs, and vanilla extract until well blended.
Pour the wet ingredients into the dry ingredients. Stir gently with a wooden spoon or use an electric mixer on low speed until just combined. Be careful not to overmix.
If using, fold in the raisins and chopped nuts evenly into the batter.
Pour the batter into the prepared baking dish and spread it evenly.
Bake in the preheated oven for 35-40 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.