Four-Layer Drip Dog Birthday Cake

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

Step 2: Grease and line the bases of two 15 cm (6-inch) cake pans that are 7.5 cm (3 inches) deep.

Tip: For other pan sizes, see the pan-size options in the recipe notes.

Step 3: Whisk together the eggs, peanut butter, oil, honey, and milk. Small lumps of peanut butter are fine.

Step 4: Stir in the carrot. Add the flour and baking soda, and stir just until combined.

Tip: Avoid overmixing.

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

Step 6: Bake for 30 minutes, or until a skewer inserted into the centre comes out clean. Cool the cakes on racks.

Step 7: Trim the mound from the top of each cake to make the tops flat. Using a serrated knife, cut each cake horizontally in half to make four even, flat layers.

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

Step 9: Whip the potatoes and yoghurt with an electric beater until as fluffy and smooth as possible, about 1 1/2 minutes on medium speed (speed 5).

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

Step 11: Use the uncoloured frosting between the cake layers to sandwich them together. Keep the rest to colour and spread over the cake.

Step 12: In a small bowl, mix the cornflour, yoghurt, and 1 tablespoon of milk to start. Aim for a consistency that spreads smoothly across the cake top while allowing drips down the side to hold their shape. Test it on a straight-sided glass. Add cornflour to thicken or more milk to thin it.

Step 13: Place one cake layer on a turntable or serving platter. Spread it with 3/4 cup of white frosting. Add another cake layer and spread with 3/4 cup frosting. Repeat once more, then place the fourth cake layer on top.

Step 14: Colour the remaining frosting blue with blue gel. To get the pictured colour, dip a toothpick into the gel and smear it on the potato frosting. Use a clean toothpick to repeat the dip and smear, then mix until the colour is uniform.

Step 15: Spread the blue frosting over the top and sides of the cake as smoothly as you can.

Step 16: Spoon 2–3 tablespoons of drip frosting onto the cake top and spread it carefully to the edge without pushing it over. Scoop up a teaspoon of frosting and drip it down the side from the top edge. Repeat around the cake, making drips of different lengths.

Step 17: Decorate the cake with decorations that will stick to the frosting. The listed decorations include silver, blue, and white balls.

Step 18: Refrigerate immediately for at least 3 hours to set the drip frosting. Keep refrigerated until ready to serve.

Tip: The recipe notes that the silver balls can sweat on the drip frosting unless it sets quickly.

Step 19: Happy birthday to your dog!