Preheat your oven to 350°F (175°C).
In a mixing bowl, combine whole wheat flour and baking powder.
In another bowl, mix peanut butter, applesauce, honey, and eggs until smooth.
Gradually add the dry ingredients to the wet mixture, stirring until well combined.
Grease a cake pan with a small amount of oil or use parchment paper.
Pour the batter into the prepared pan and spread evenly.
Bake in the preheated oven for 25 minutes or until a toothpick comes out clean.
Let the cake cool in the pan for 10 minutes, then transfer it to a wire rack.
Once cooled, frost the cake with plain yogurt.
Decorate with carob chips or additional yogurt if desired.