Preheat the oven to 160ºC
Grease a round tin and line with parchment paper
Fit the K beater to the machine
Add Ingredients 1 (butter, sugar) into the Mixer bowl
Attach the Mixer bowl to the machine and fit the splash guard
Mix on speed 3 for about 2 minutes until combined
Add Ingredients 2 (egg) to the bowl
Mix on speed 2 for about 2 minutes until incorporated
Add Ingredients 3 (polenta, flour, baking powder, orange juice and zest, lemon juice and zest) into the Mixer bowl
Mix on speed 2 for about 2 minutes until combined
Pour the batter into the tin
Bake at 160ºC for 45-50 minutes until a skewer inserted comes out clean
Turn out onto a cooling rack to cool
Add Ingredients 4 (juice, sugar) into a small saucepan
Heat on a medium-high heat until boiling and reduce the heat
Simmer for 5 minutes
Drizzle the glaze over the still warm cake