In a large bowl, combine ground beef, breadcrumbs, egg, garlic powder, dried onion, salt, and black pepper. Mix until just combined and form into patties.

Heat a nonstick skillet over medium heat and add olive oil and unsalted butter. Sear the patties for about 5 minutes on each side until golden brown.

In the same skillet, add minced garlic and yellow onion. Stir for about 2 minutes, then add salt, pepper, and Italian seasoning followed by tomato paste. Cook for another minute.

Pour in heavy cream and stir. Add spinach until wilted, then fold in sun-dried tomatoes and Parmesan cheese, bringing to a gentle simmer.

Return the seared hamburger steaks to the skillet, allowing them to simmer in the sauce for another 5 minutes before serving.