Boil eggs for 6 minutes, then cool in cold water and peel. Coat peeled eggs with flour.

Mince onion and microwave for 30 seconds at 600W to soften. Let cool.

Mix breadcrumbs with milk in a bowl. Add ground meat, onion, salt, and pepper. Mix until sticky.

Divide meat mixture into two portions. Flatten each to 1cm thickness, place an egg in the center, and wrap to form patties.

Heat salad oil in a pan over medium heat. Cook patties until browned, then flip and cover. Cook on low heat for 8 minutes.

Remove patties and clean the pan. Add sauce ingredients and cook over medium heat until butter melts and sauce thickens.