Preheat and prep: Heat oven to 350°F (175°C). Grease a 6-inch round cake pan or line a muffin tin if making pupcakes. You can also use a small loaf pan.

Mash the wet ingredients: In a medium bowl, mash the banana. Stir in pumpkin puree, peanut butter, eggs, and applesauce until well combined and smooth.

Combine dry ingredients: In another bowl, whisk whole wheat flour, oats, and baking powder to evenly distribute the leavener.

Make the batter: Add the dry mixture to the wet ingredients. Stir just until combined. If the batter seems too thick, add water 1 tablespoon at a time until it’s scoopable but not runny.

Fold in extras: If using shredded carrot or blueberries, fold them in gently. Keep mix-ins modest so the cake bakes evenly.

Fill the pan: Spread the batter into your prepared pan, smoothing the top. For cupcakes, fill each well about 3/4 full.

Bake: Bake a 6-inch cake for 22–28 minutes, or cupcakes for 14–18 minutes. You’re looking for a firm top and a toothpick that comes out mostly clean.

Cool completely: Let the cake rest in the pan for 10 minutes, then transfer to a rack to cool fully. Do not frost a warm cake—the yogurt frosting will melt and slide off.

Make the frosting: Stir Greek yogurt and peanut butter until creamy and spreadable. If you want it stiffer for piping, chill it for 10–15 minutes.

Decorate: Spread or pipe frosting over the cooled cake. Decorate with a few blueberries or small carrot curls for color. Skip candles if your dog is prone to getting too close.

Serve: Slice a small piece appropriate for your dog’s size. Start with a few bites if your pup has a sensitive stomach or isn’t used to rich treats.