Beef Stew (Karne Asada)

2 pounds beef sirloin, cut into 3-inch cubes
2 tablespoons lemon juice
2 tablespoons soy sauce
1 1/2 tablespoons cornstarch
1/4 teaspoon Maggi sauce or soy sauce
Patis or salt and freshly ground pepper to taste
2 large potatoes, sliced in rounds
2 large onions, sliced in rings
3 tablespoons oil

Marinate the sirloin cubes in lemon juice, soy sauce, cornstarch, Maggi, patis or salt and pepper for 30 minutes. Then, over a low flame, simmer the marinade and the sirloin for 1 hour.

In a skillet, fry potatoes and onion rings in oil separately. Arrange beef on a platter with potatoes and onion rings on top.