Dry the eggs well before wrapping – any moisture will stop the sausage sticking and can cause gaps when frying. | Flatten the sausage evenly rather than too thick in one spot, this helps it cook through properly without overcooking the outside. | Don’t overcrowd the pan when frying – the oil temperature will drop and you’ll lose that crisp coating. | If the oil is browning too quickly, lower the heat slightly and keep turning the eggs so they colour evenly. | You can use the leftover bacon fat to cook the onions for the ketchup to carry that flavour all the way through.