2) In a large bowl, whisk together the polenta, flour, baking powder and salt.
3) In a standing mixer fitted with the paddle attachment, or with a hand-held electric mixer and a large bowl, combine the butter and sugar and mix until light and airy. Add the eggs one at a time, mixing well between each addition.
4) Add the polenta mixture to the butter mixture in 3 parts, alternating with the milk in 2 parts, until just combined into a thick batter. Using a rubber spatula, scrape the batter into the prepared skillet and smooth the top.
5) Bake until lightly browned and a toothpick inserted in the centre comes out clean, about 30 mins. Set aside to cool slightly before serving.