In a large bowl, combine grated onion, ground beef, breadcrumbs, salt, pepper, heavy cream, and the egg. Mix gently until just combined.

Divide the mixture into four equal portions and shape into patties about ¾ inch thick.

Heat olive oil and unsalted butter in a skillet over medium heat.

Sear the patties in the hot skillet for 4-5 minutes on each side until golden brown.

In the same skillet, add diced onion and minced garlic; sauté for about 2 minutes.

Sprinkle in salt, pepper, and all-purpose flour, cooking for another minute while stirring.

Slowly add chicken broth, scraping the bottom of the pan, and simmer for about 2 minutes.

Pour in heavy cream and add chopped dill, bringing the sauce to a gentle boil.

Return the seared hamburger steaks to the skillet and simmer for about 5-6 minutes.

Garnish with additional chopped dill and serve with mashed potatoes or bread.