Sweet Potato cakes

In future if I had the decison of making these again or just cutting up some sweet potato wedges, I think I might go with the latter. I liked them, but they were very messy to make and quite difficult to manouevre once they were in the frying pan. I did try to work with the sweet potato while it was still hot, the recipe does say to leave it for an hour to drain before mixing.  They may have been easier to make if the mixture had been cold. The recipe came from a cookbook called 'Plenty' by Yotam Ottolenghi. Saying that, as a meat free meal, they were substantial and flavoursome. 

Ingredients 
Serves 4
1kg sweet potatoes, peeled and cut into large chunks
2 tsp soy sauce
100g flour
1 tsp salt
½ tsp sugar
3 tbsp spring onion, chopped
½ tsp fresh chilli, finely chopped (or more, to taste)
Lots of butter, for frying or oil

For the sauce:
50g Greek yogurt
50g sour cream (I left this out)
2 tbsp olive oil
1 tbsp lemon juice
Salt and pepper
1 tbsp fresh coriander, chopped

Steam the sweet potato until soft, then drain in a colander for an hour. Meanwhile, whisk the sauce ingredients until smooth and set aside. In a mixing bowl, work all the fritter ingredients by hand - it should be sticky, so if it's a little runny, add some flour. Do not over-mix.
Dip your hands in water and shape walnut-sized balls with the fritter mix, then flatten so you have round cakes around 5cm in diameter and less than 1cm thick. Place on an oily surface.
Melt some butter in a nonstick pan. Using a fish slice, lift the cakes in to the pan and fry on moderate heat until you get a nice, brown crust, turning as necessary - about six minutes. Place between two sheets of kitchen towel, to soak up the excess butter. Serve hot or warm, with the sauce on the side and a crisp green salad.