To begin making the the Mexican Brown Rice and Quinoa Casserole, first clean, wash and soak the brown rice in water for about 15 to 20 minutes. Once soaked drain the soaked rice in a colander and keep the rice aside.

Next heat olive oil in a large skillet over medium high heat. Add chopped garlic and green chilies and saute for a few seconds. Add the chopped bell peppers, sprinkle some salt and stir fry on medium heat until the peppers have slightly softened.

Once cooked, add in the chopped tomatoes and the cooked beans and cook until the tomatoes soften.

Add the drained rice along with quinoa, chili powder and cumin powder to the onion tomato mixture. Stir to combine and saute for few minutes. Add the hot vegetable stock, stir and season with salt and black pepper to taste. 

Bring the brown rice and quinoa mixture to a brisk boil once over medium high heat.

Once it comes to a brisk boil, cover with the lid, reduce heat and cook until rice is cooked through and all the water is absorbed.

Turn off the heat at this stage and allow the rice to rest for about 5 minutes. After 5 minutes, open the lid and fluff the rice and quinoa with the a fork. Stir in the avocados, lemon juice and chopped coriander. Check the spice levels and adjust to suit your taste. 

Take care to stir gently so the rice and the vegetables don't get mashed up. Transfer the casserole to a serving dish and serve warm.

Serve Mexican Brown Rice and Quinoa Casserole along with chilled a Yogurt Dip or Mexican Chilli for a wholesome weeknight dinner.