Prepare the Steaks: In a bowl, gently mix minced onions, shredded butter, garlic, Worcestershire sauce, mustard, and meat. Don’t overmix.
Shape into oval steaks and refrigerate for 15 minutes. Season both sides with salt and pepper.
Heat olive oil in a skillet over medium-high heat. Sear steaks for 2-3 minutes on each side. Set aside.
Make the Gravy: Lower heat to medium-low. Melt 2 tablespoons butter in the skillet, add onions, and cook until caramelized (15-20 minutes).
Add chicken broth, beef broth, onion powder, garlic powder, and Worcestershire sauce. Scrape up any browned bits from the bottom of the pan.
Mix cornstarch and cold water until smooth. Bring gravy to a boil, whisk in cornstarch mixture, and cook until thickened.
Finish the Dish: Add steaks back to the skillet, spoon gravy over them, cover, and cook for 10 minutes until the internal temperature is 160°F.
Swirl in 1 tablespoon cold butter for a smooth finish. Sprinkle with parsley and serve with mashed potatoes and roasted carrots.