For making the patties:
In a mixing bowl, combine ground beef, bread crumbs, egg, salt, and pepper. Mix well.
Get at least 1/4 cup of the mixture. Roll into a ball then flatten using your clean hands.
Heat cooking oil in a pan. Fry the patties until brown on both sides.
Remove from the pan then drain excess oil. Set aside.
For making the mushroom gravy:
Melt butter in a pan (set in medium heat).
Add the garlic. Sauté for 1 minute.
Add the button mushrooms. Sauté for 1 minute.
Add the all-purpose flour. Mix until dissolved.
Add the water with beef cube. Stir well.
Adjust to low heat. Simmer until the sauce thickens. (Tip: if you notice that the gravy is too thick, add some water)
Pour the mushroom gravy over the fried patties.
Serve with steamed rice. Enjoy your Jollibee-style burger steak with mushroom gravy!