Preheat a conventional oven to 180°C
Line or grease 10 muffin holes in a 12-hole muffin tray
Clean whole sweet potato and grate (no need to remove the skin)
In a large bowl, mix together the flour, oats, baking powder and the spices
In a separate bowl, mash the banana and mix with the egg, milk and olive oil. When combined, add the grated sweet potato, and stir until mixed through and a thick batter has formed
Add the dry ingredients into the banana and sweet potato batter and stir until well combined and no flour is visible
Divide the batter into the muffin liners evenly
Place in the preheated oven and bake for 35 minutes, or until the muffins are beginning to brown on top and they are cooked through when pierced with a skewer
Remove from the oven and place the muffins on wire rack to cool