Squeeze the sausage meat out of their cases and roll into balls. I get three balls from each fat sausage.
Add the oil to a heavy based non stick pan and fry the sausage balls over a medium heat until browned all over.
Turn the heat to low and add the onions and a scattering of sea salt flakes. Allow to cook for a few minutes until softened.
Meanwhile, grate the sweet potatoes, skin and all, into a clean tea towel then squeeze over the sink to remove any excess liquid from the potatoes. Add this to the pan and cook until cooked through.
When everything in the pan has cooked through, turn grill on. Using a wooden spoon make 4 holes in the mixture large enough to take the eggs.
Crack the eggs into the holes and continue to cook until set on the bottom, then place under the grill to cook until the tops have set to your liking. Sprinkle the yolks with some more salt and give a grind of fresh pepper before serving.