Heat the cooking oil in a wide cooking pot over medium heat.
1/4 cup cooking oil
Dredge the sliced lengua in flour and shake off the excess. Pan-fry for about 1 minute per side or until lightly browned. Remove from the pot and set aside.
2 lbs beef lengua, 1/2 cup all-purpose flour
Using the same pot, sauté the onion and garlic until the onion becomes soft and aromatic.
1 pieces medium yellow onion, 3 cloves garlic
Pour in the diced tomatoes and white wine. Stir and allow the mixture to simmer for 2 minutes.
1 can diced tomatoes, 3/4 cup white wine
Return the pan-fried beef lengua to the pot.
2 lbs beef lengua
Stir in the soy sauce and water, then add the beef bouillon. Bring everything to a boil.
2 tablespoons soy sauce, 1 cup water, 2 teaspoons beef cube
Add the bay leaves. Cover the pot and cook over low heat until the sauce reduces to about half.
5 pieces bay leaves
Pour in the vinegar and allow the sauce to re-boil.
1 tablespoon vinegar
Add the brown sugar, green olives, black olives, and mushrooms. Stir and cook for 5 to 8 minutes.
2 tablespoons brown sugar, 1 cup green olives, 1/4 cup black olives, 1/2 cup button mushrooms
Season with salt and ground black pepper to taste.
salt and ground black pepper
Transfer to a serving plate and serve warm.