Various origin stories exist. The Oxford Companion to Food gives the first instance of the name as of 1809, in an edition of Maria Rundell's A New System of Domestic Cookery. They did not, at that time, have a breadcrumb layer, although by 1861 Isabella Beeton suggested this as an option
6 large eggs 1 cup all-purpose flour 1 cup finely crushed corn flakes 7 Vegetable oil (for frying) Kosher salt freshly ground pepper Mustard
Step 1 Place 4 eggs in a small saucepan; add cold water to cover. Bring to a boil; remove from heat, cover, and let stand for 3 minutes. Transfer eggs to an ice water bath. Gently crack shells and carefully peel under cold running water. Place eggs back in bowl of cold water; cover and chill until cold.
Step 2 Place flour in a wide shallow bowl and crushed corn flakes in another wide shallow bowl. Divide sausage into 4 equal portions. Pat 1 portion of sausage into a thin patty over the length of your palm. Lay 1 soft-boiled egg on top of sausage and wrap sausage around egg, sealing to completely enclose. Repeat with remaining sausage and eggs.
Beat the remaining egg and put on a plate. Put the flour and breadcrumbs on two separate plates. Roll the encased eggs in the flour, then the beaten egg and finally the breadcrumbs. Can be prepared up to a day in advance.
To cook the eggs, heat 5cm of the oil in a wide saucepan or wok until it reaches 160C on a cooking thermometer or until a few breadcrumbs turn golden after 10 secs in the oil. Depending on the size of your pan, lower as many eggs as you can into the oil, and cook for 8-10 mins until golden and crispy. Drain on kitchen paper, leave to cool a little, then serve halved with some piccalilli