Dog Birthday Cake with Whipped Potato Frosting

Step 1: Preheat the oven to 180C/350F (160C fan).

Step 2: Grease and line the base of two 20cm/8-inch cake pans.

Step 3: Whisk together the eggs, peanut butter, oil, honey, and milk. A few small peanut butter lumps are fine.

Step 4: Stir in the carrots. Add the flour and baking soda, then stir just until combined. Overmixing can make the cake hard.

Step 5: Divide the batter between the cake pans, then spread it out and smooth the surfaces.

Step 6: Bake for 25 minutes, or until a skewer inserted into the centre comes out clean.

Step 7: Cool the cakes on racks before frosting.

Step 8: Boil, steam, or microwave the potato until very soft.

Step 9: Whip the potato and yogurt with an electric beater until as fluffy and smooth as possible. It will not become completely smooth; beat for about 1 1/2 minutes on medium speed.

Step 10: Add water as needed to loosen the frosting to a soft, spreadable consistency. Use it while warm; it sets as it cools.

Step 11: Spread one quarter of the frosting over one cake layer.

Step 12: Place the second cake layer on top. Frost the top and sides with the remaining frosting, reserving some for piped decorations if desired.