Prepare the ingredients: Dice the onion and mince the garlic.

Mix the patty ingredients: Combine ground beef, egg, breadcrumbs, salt, black pepper, dried onion, and Dijon mustard in a bowl.

Shape the patties: Form meat mixture into four equal patties.

Sear the patties: Heat oil and butter in a skillet and sear each patty for about 5 minutes on each side.

Sauté the aromatics: Cook the remaining onion and garlic in the skillet until softened.

Deglaze the pan: Add white wine and scrape the bottom of the skillet, letting it reduce for 2 minutes.

Create the sauce: Stir in cream, horseradish, and Parmesan, cooking until thickened.

Combine and simmer: Return the patties to the skillet and let simmer in sauce for 5 minutes.

Serve and garnish: Plate the patties and top with chives before serving.