Preheat your oven to 350°F (175°C) and grease your 9-inch round cake pan with a little vegetable oil or line it with parchment paper.
In a mixing bowl, whisk together the whole wheat flour and baking soda until well combined.
In another bowl, combine the vegetable oil, natural creamy peanut butter, plain applesauce, pumpkin puree, shredded carrots, milk, and egg. Mix until smooth and well incorporated.
Gradually add the dry ingredient mixture to the wet ingredients, stirring until just combined. Be careful not to overmix.
Pour the batter into the prepared cake pan and spread it evenly. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
Once baked, remove the cake from the oven and let it cool in the pan for 10 minutes. Then, transfer it to a cooling rack to cool completely.
While the cake cools, prepare the frosting by mixing the plain Greek yogurt and natural creamy peanut butter in a bowl until smooth and creamy.
Once the cake is completely cool, spread the peanut butter yogurt frosting generously over the top and sides of the cake.
If desired, decorate the cake with dog treats for a fun and festive touch. Serve a slice to your furry friend and enjoy the celebration!