Tex Mex lentil casserole

This is a pretty fast and easy dish to make. I think I found the recipe online at some point.

1 C red lentils (I've used brown ones too and it works fine)
1 can vegetable stock (if I was out of veggie stock I've used chicken which also worked well although obv. wouldn't be vegetarian if you went that route)
1 C chopped onion
1 can diced tomatoes (I like to use the ones w/the chilies but plain is fine)
1 tsp chili powder
1/4 tsp ground cumin
1/2 C grated fat-free cheese
2 T chopped cilantro if desired

Combine all the ingredients except cheese and cilantro in 1 1/2 qt covered microwaveable dish. Microwave on high for 18-20 mins. (Depending on the strength of your micro, you may need to do it a little longer than that...keep an eye on the container near the end of the cooking time, and adjust accordingly.) Carefully remove cover and stir, sprinkle with cheese, cover and let stand for 20 mins. Garnish with cilantro.