Lomo Saltado - Peruvian Stir-Fried Beef

Ingredients

• 600 g (1.3 lbs) of entrecote cut in thick pieces
• 2 red onions cut into pieces
• The stalk of a spring onion cut into pieces
• 1 yellow chili bell pepper cut into thin strips
• 1 tomato cut in strips (without the pulp)
• 1 crushed garlic clove
• 3 tablespoons soy sauce
• 2 tablespoons white wine vinegar
• Salt and pepper to taste
• Olive oil