Purple Sweet Potato Muffins

I was just finishing up the Ogura cake for my sister, and wanted to make use of the oven (since it took so long to heat up and cool down anyway!). Googled and found a recipe for sweet potato muffins, which were easy enough to whip up (I had less than an hour before I had to pick Y from school then)

Sweet Potato muffins (makes 12) 

1 Cup Self-raising flour

1 Cup sugar (I used 3/4C)

1 tsp cinnamon powder

1/2 egg

1 Cup mashed sweet potato flesh

1/2 Cup oil

Steps

1. Line a 12-hole muffin pan with liners, if using. Preheat oven to 375F/190C.
2. Sift the dry ingredients (flour, sugar, cinnamon)
3. Beat the egg til pale, then add the sweet potato flesh and oil. Mix well. 
4. Mix the dry ingredients into the wet ingredients, until just moistened.
5. Bake in preheated oven for 15-18 minutes.

Note: for some reason, the baked purple sweet potato turns green, so my sisters and nephews were a bit hesitant to eat when they saw green spots dotting the muffin (looking exactly like mouldy food) I read later that it was due to a reaction with baking soda/powder. 

Purple Sweet Potato muffins waiting to be consumed