Add fire roasted tomatoes, tomatoes with chilies, tomato paste, vegetable stock, mung beans and garlic to a slow cooker and turn it on high an cover for 2 hours.

Meanwhile, add garam masala to a small frying pan and roast over a low flame, stirring constantly for about 3 minutes. When it begins to smell a bit more pungent, take it off the stove and add it into the contents of the slow cooker.

Then, add some olive oil to the same frying pan and add the onions to it. Let the onions caramelize over a low flame, stirring often - when well caramelized (about 20-25 minutes) add it to the slow cooker as well.

Also at this point, add in the cocoa, chickpeas and black beans. Place the lid on and let it cook.

When it's done, turn the slow cooker onto low for another hour and then this Slow Cooker Three Bean Stew With Cocoa is ready to enjoy.