In a bowl, combine the beef cubes with soy sauce and lemon juice or vinegar. Mix well and marinate for at least 30 minutes, or for better flavor, leave it in the refrigerator overnight.

Heat vegetable oil in a large pot over medium-high heat. Remove the beef from the marinade (reserve the marinade) and brown the beef on all sides. Do this in batches to avoid overcrowding the pot. Set the browned beef aside.

In the same pot, add a bit more oil if needed. Sauté the garlic and onion until translucent and fragrant.

Return the browned beef to the pot. Add the reserved marinade, diced tomatoes, tomato sauce, beef broth or water, and bay leaves. Bring to a boil, then reduce the heat to low, cover, and simmer for 1.5 to 2 hours, or until the beef is tender.

Once the beef is tender, add the potatoes and carrots. Continue to simmer until the vegetables are cooked, about 20 minutes. Add more broth or water if the stew is getting too thick.

Add the red bell pepper strips and green peas (if using). Season with salt and pepper to taste. Simmer for an additional 5 minutes, or until the bell peppers are tender but still crisp.

Remove the bay leaves. Serve the Mechado hot with steamed rice, enjoying the rich flavors of the sauce with the tender beef and vegetables.