Soak brown rice in water for 15-20 minutes.

Drain the soaked rice in a colander.

Heat olive oil in a large skillet over medium-high heat.

Add minced garlic and chopped green chilies and saute for a few seconds.

Add chopped bell peppers, sprinkle some salt and stir fry until the peppers have slightly softened.

Add diced tomatoes and 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 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 and allow the rice to rest for about 5 minutes.

After 5 minutes, open the lid and fluff the rice and quinoa with a fork.

Stir in the avocados, lemon juice and chopped coriander.

Check the spice levels and adjust to suit your taste.

Transfer the casserole to a serving dish and serve warm.