Preheat oven to 350 degrees F

In a large bowl, combine flour and baking soda.

In a separate bowl mix together vegetable oil, peanut butter, applesauce and pumpkin puree, and egg. Mix until combined.

Combine wet and dry ingredients and stir.

Pour mixture into an 8" round pan greased with oil. You can also use a square pan.

Bake for about 25-30 minutes. A toothpick inserted into the center should come out clean.

Allow to cool on a wire rack before removing from the pan. Add icing if desired.

Combine greek yogurt and peanut butter. Allow cake to cool completely before frosting.