garden salad, buttered corn kernels, or green beans
Form and Sear the Steaks
In a large bowl, gently mix together the ground beef, breadcrumbs, beaten eggs, onion, garlic, rosemary, mustard, worcestershire, salt and pepper. Combine just until the mixture is blended to avoid overmixing, which will make the meat tough and gummy.
Scoop up the meat mixture with a #12 (2 ounce) portion scoop, or use a 1/3 measuring cup and drop the balls onto a sheet pan or tray.Form the portions into a football before flattening each with the palm of your hand into an 1/2" thick, oval-shaped patty.
Cook the Salisbury steaks: heat the vegetable oil in a skillet over medium-high heat. Press the patties into the pan and sear them on both sides- this should take about 4 minutes per side. The patties won't be cooked through. Transfer the patties to a plate while you prepare the mushroom gravy.
Make the Mushroom Gravy
Drain off all but 2 tablespoons of grease from the pan. Decrease the temperature to medium. Saute the sliced portobello mushrooms in the oil for 10 minutes, or until they are golden brown.
Sprinkle the all-purpose flour over the mushrooms and stir together to create a roux. Cook the roux for 3 minutes, stirring frequently, until it emits a nutty aroma and turns brown.
Pour 1 cup of the beef stock into roux and stir until it forms a thick paste. After the paste forms, continue adding the stock in stages- stirring constantly- to develop a smooth liquid in the pan. The gravy will thicken as it cooks, so don't worry if it appears a little thin at this point. Add the remaining rosemary to the pan gravy, then allow the gravy to come to a boil.
Finish cooking the Salisbury Steaks
Decrease the temperature, once again, to low. Return the steaks to pan. Cover the pan and allow the patties to simmer over low heat for 10 minutes, or until the center of the patty reaches an internal temp of 160°F. If the patties aren't completely covered by the gravy, flip them over after five minutes of simmering to ensure they're cooked thoroughly.
Serve your Salisbury steaks while hot with a side of mashed potatoes.
Instructions for freezing prior to cooking:
Lay the formed patties on a lightly greased sheet pan. Cover the pan lightly in plastic wrap and freeze the patties until solid.
Once frozen, transfer the patties to a freezer storage bag and seal. The patties may be kept frozen for up to 6 months.
To prepare, allow the patties to thaw completely, under refrigeration, before searing
Instruction for freezing after cooking:
Allow the Salisbury steak and gravy to cool to room temperature.
Transfer to a freezer storage bag (double-bagging is recommended). Place the sealed bag in the freezer lying flat.
Once frozen solid, stand the flat bag upright- this takes up less space in the freezer.
To heat, allow the Salisbury steak to thaw completely in the refrigerator. Empty the contents of the bag into a skillet or a microwave bowl and reheat on the stove or in the microwave until steaming hot.