Preheat oven to 180°C/350°F (160°C fan). Line a 12 hole muffin tin with cupcake liners.

Place bananas in a bowl and mash with a potato masher until smooth as you can get it.

Add peanut butter, honey and eggs. Whisk well until smooth.

Add flour, baking powder, oil and water. Whisk until smooth.

Divide between cupcakes until 3/4 full. Bake 22 minutes until the top is golden, or skewer comes out clean.

Transfer to cooling rack and cool for 30 minutes before topping with "frosting"

Place potato in a large pot of water. Bring to boil, then cook potato for 20 minutes until very, very soft and starting to crumble on the edges.

Drain, then return into empty pot. Add yogurt, honey and water (starting with 2 tbsp). Beat with electric beater for 1 minute on speed 3, increasing to speed 5, for 1 minute or until smooth and creamy. Add more water if needed - it should have a soft consistency like frosting.

Transfer to piping bag fitted with a 1.5cm / 3/5" round nozzle (Note 3 for other nozzles). Pipe in swirling motion onto cupcakes, top with dog biscuit.