Finely dice the onion and chop the garlic. Peel and dice the sweet potato into 1cm cubes.
Place the frypan over medium heat and add a splash of evoo, once hot add the sweet potato and saute´ for 2 minutes.
Next add the onion and continue to saute´ for another minute, then add the garlic and saute´ for a further 30 seconds.
Add the rice to the pan and toast it for 2 minutes then add the stock and seasoning and bring to the boil. Place the lid on the pan and place the pan into a pre-heated oven steam setting 100 °C for 14 minutes.
Once cooked remove the pan from the oven and add the butter and parmesan and stir through until the butter is melted and combined.
Transfer the rice to a mixing bowl and cool completely.
Once cool chop the coriander and mix it through the rice. Set up a bowl of cold water and spoon out the rice into golf ball sized balls, dampen your hands with the water to help shape the balls and ensure the rice does not stick to your hands.
Dust a large baking tray with flour and toss the risotto balls in the flour until evenly coated with flour.
Whisk together the egg and milk and place the floured risotto balls into the egg wash then into a bowl of breadcrumbs.
Place the crumbed balls onto a baking tray lined with baking paper and spray the balls lightly with oil spray. Place the tray into a pre-heated oven combi setting 210 °C for 20-25 minutes until crisp and golden brown.
Once cooked remove the arancini from the oven and place them on a large serving platter. Squeeze a dollop of kewpie mayonnaise on to the top of each arancini and finish with a small “dot” of sriracha sauce on top of the mayonnaise and serve.