Grease a small microwave-safe bowl with butter.
Place the butter, polenta, flour, sugar, eggs and lemon zest into a food processor and blend until smooth. Pour the cake mixture into the greased bowl and cover with cling film.
Place into the microwave and cook on the highest power for 5-8 minutes, until cooked through. You can test this by piercing the cake with a skewer and removing it - if the skewer comes away clean then the cake is ready.
For the lemon icing, sift the icing sugar into a bowl, add the lemon juice and mix well.
To serve, tip the pudding and bowl upside-down onto a plate and remove the bowl. Drizzle over the lemon icing and honey and garnish with fresh mint.