Start by dicing the yellow onion and mincing the garlic cloves, setting them aside for later use.

In a large mixing bowl, combine the ground beef, breadcrumbs, egg, Dijon mustard, salt, pepper, and dried onion. Mix gently until just combined.

Divide the meat mixture into four equal portions and flatten each into ¾ inch thick patties.

Heat olive oil and butter in a skillet over medium-high heat. Sear the patties for 5 minutes on each side until golden brown.

Remove patties and sauté diced onion and minced garlic in the same skillet for about 3 minutes until translucent.

Pour in the dry white wine and simmer for about 2 minutes, scraping up brown bits from the skillet.

Add heavy cream, stir until boiling, then mix in grated Parmesan and horseradish until creamy.

Return the patties to the skillet and simmer for 5 minutes to meld flavors.

Plate the Salisbury steaks and ladle the sauce over them, garnishing with chopped chives before serving.