Mince the onion.

Heat 1 tbsp salad oil in a pan, sauté the onion on low heat until translucent, then let it cool.

In a bowl, soak breadcrumbs in milk. Add ground meat, salt, pepper, and nutmeg, then knead until sticky. Mix in the cooled onion and form into two oval patties with a slight indentation in the center.

Heat 1 tbsp salad oil in a pan, cook the patties on medium heat until browned on both sides. Cover and cook on low heat for 7 minutes.

Remove the patties, add all sauce ingredients except butter to the pan, and simmer on medium heat.

Add butter to the sauce and stir until melted.