Filipino Burger Steak

For the burger patties:
1. In a mixing bowl, combine ground beef, Dijon mustard, onion, garlic, egg, salt and pepper. Mix with a wooden spoon or with your hands until well combined.
2. Depending on your preferred thickness and size of the patty, scoop the mixture and shape into a burger patty. This can be done by rolling the mixture into equal-sized balls then flattening them on a flat surface or using the palms of your hands to shape and flatten.
3. Fry burger patties in a preheated pan or grill over medium high heat. Cook each side for 2 to 3 minutes depending on thickness. Continue to fry all your patties, then set aside.

For the mushroom gravy:
1. Melt the butter in a saucepan over medium-high heat. Add the mushrooms and saute for about 10 minutes or until brown and the mushroom juices evaporate. Stir in flour and reduce the heat to medium, cook for another 3 minutes.
2. Whisk in 1 cup of beef broth, then add the rest once the first cup is incorporated. Add the thyme and reduce the heat to low. Let it simmer for about 20 minutes. Sprinkle salt and pepper in according to taste.
3. Serve mushroom gravy on top of burger patties. Serve with mashed potatoes or steamed rice.