i`ll go and look for a proper recipe in a minute but from memory:

hard boiled eggs
sausage meat
pre-toasted and crisped breadcrumbs.

assemble in the normal fashion and bung in the microwave on full power for 10 minutes BUT microwaves have moved on a bit since i last made them about 15 years since so the timing might want looking at.

edit: i can only find one recipe and her timings are the same as mine so i would experiment a bit.

I've made them with grated cheese instead of sausage meat. You just clagg it around the hard boiled egg then squash the bread crumbs on. Scrummy.

Hubby makes them from scratch (deep fried) and they're amazing, so different from shop bought. Daughter wont eat boiled egg so we put a mozzerella ball in the middle for her

we bought Indian spiced ones once from a farmers market. , they were delicious too. IIRC it was minced chicken rather than sausage meat

I've heard of people using minced beef and adding indian spices to that instead of sausage meat, never heard of using chicken before.

Good idea about the mozzarella balls, might give it a go

On Couple's Come Dine With Me today, someone made Scotch Eggs, with black pudding and pickled eggs.

Sounded very nice.