Mix all the steak ingredients (beef, eggs, Baking Blend, Worcestershire sauce, salt, pepper, garlic powder, and black pepper) together. Form into 8 oval-shaped patties.

Melt 4 tablespoons butter in a large, preheated skillet over medium-high heat. Add the patties (do in batches and add more butter if necessary). Cook for 6 minutes then flip and cook for an additional 4 or 5 minutes or until cooked to desired temperature. Remove from skillet and set aside.

Melt remaining 4 tablespoons butter in the skillet. Add the onions and mushrooms. Sauté over medium heat, covered, stirring occasionally, until tender and beginning to brown.

Add the beef stock, apple cider vinegar, salt, garlic powder, onion powder, and pepper. Bring to a slow-rolling boil.

In a glass bowl, beat the egg yolks.

Now it is time to temper the egg yolks (to prevent them from coagulating). While whisking BRISKLY with one hand, SLOWLY pour a ladle's worth of hot liquid from the skillet into the bowl with the egg yolks. Beat quickly so that it mixes rather than coagulates. Repeat with a second ladle's worth of liquid. Then pour this egg yolk mixture into the skillet and whisk into the rest of the liquid.

Heat the gravy, stirring constantly, over medium to medium-high heat until slightly thickened.

Add the patties to the gravy and allow to reheat.

Serve, sprinkling as much shredded cheese atop as you like.