Heat olive oil in a large pot over medium heat. Add onions, carrots, garlic, and chile pepper; cook and stir until tender, about 3 to 5 minutes. Mix in tomatoes, vegetable stock, 1/2 of the cilantro, balsamic vinegar, sugar, brown sauce, and Worcestershire sauce. Season with salt and pepper. Bring to a boil. Reduce heat to low, and simmer 30 minutes.