Pre-heat oven to 170°C and grease and flour a 10 inch bundt tin.
First of all prepare the cinnamon swirl by mixing all the ingredients together in a small bowl and then set aside.
For the cake, sift together, in a large bowl, the flours, bicarbonate of soda, baking powder, salt and pepper, then set aside.
In another bowl beat together the sweet potato, cream cheese and vanilla extract. Again, set aside.
Beat the sugars and butter together in a food mixer until well incorporated.
Add in the eggs one at a time until the batter is smooth.
Finally spoon in 1/3 of the flour, beat into the batter then add 1/3 of the sweet potato mixture and beat in. Repeat until all the flour and the sweet potato mixture has been incorporated into the batter.
Spoon 1/3 of the batter into the prepared bundt tin and smooth down. Dot half of the cinnamon swirl mixture in and swirl with a cocktail stick.
Spoon the next 1/3 of the batter and repeat with the cinnamon swirl.
Spoon the rest of the batter in, smoothing the surface.
Bake for about 50 minutes.
Remove from the oven, rest for five minutes and then carefully remove the cake from the bundt tin. Cool completely on a wire rack then drizzle with the maple cream cheese icing.
Finally spinkle some extra cinnamon over the top of the cake.
For the maple cream cheese icing beat the icing sugar together with the salted butter and cream cheese until smooth.
Then add the whole milk and maple extract and beat until combined.