Chop 1/4 of the sweet potato into even smaller pieces and set aside. Place the sweet potato, avocado, almonds, polenta, maple syrup, eggs, baking powder, bicarb, milk and 1/4 tsp salt in the bowl of a food processor. Blend until completely smooth. Divide the mixture evenly between the muffin tin holes, then top with the reserved chopped sweet potato, feta, seeds and a dusting of paprika. Bake for 22 mins, or until risen, browning on top and cooked through – check by inserting a skewer to the centre, it should come out dry. Cool in the tin for 5 mins, then transfer to a wire rack and cool completely. Store in a sealed container for up to 3 days.