Trim the steak of visible fat and gristle, and cut it into 1-inch squares.

Clean the mushrooms and halve or quarter them if larger. You want them about the same size as the steak chunks.

Mix the steak and mushrooms with the garlic, Dijon mustard, 2 tbsp of olive oil, dehydrated onion flakes, and Worcestershire sauce. Mix well to coat.

Add 1 tbsp of oil to a large skillet and preheat the pan over fairly high, but not scorching hot, heat. Working in two batches, add the meat and mushroom mixture, stirring it a few times to allow for even browning. Cook it for approximately 2-3 minutes for medium-rare beef, another minute or so for more well-done beef. Test the doneness of the beef by cutting into one of the cubes, and cook longer if necessary. Remove from the pan and set aside.

Cook the remainder of the beef in the remaining oil, taking care not to overcook the beef.

Serve with your favorite sides!