Make a paste of onion and curly parsley (using food processor); then I added in the mixture into the ground beef along with an egg, salt, pepper, and nutmeg. Shape them as patties/burger and place them on a baking sheet that was already covered with aluminum foil. On top of each burger, place tiny cube of butter.

Preheat the oven to 350 F and bake the burgers for 40 minutes (or until cooked).

Meanwhile, melt some butter and fry onion ring until translucent