Heat the oil in a large frying pan over medium-high heat. Add the red onion and Mexican seasoning. Cook while stirring, for 3 minutes.

Add the carrot, bell pepper, and mushrooms, and cook while stirring for 5 minutes, until vegetables start to soften. Add the canned diced tomatoes, ¾ cup of beans and ½ a cup of water. Bring to a simmer. Partially cover and cook, stirring occasionally, for 10 minutes or until the mixture thickens.

In a bowl, combine tomato, cilantro, lime juice and remaining beans.

Divide the chili between two serving bowls. Top with tomato and bean mixture. Season with pepper and serve.