If you have a slow cooker that has a stovetop setting, heat it to high and add the onions. If you do not have a slow cooker with a stovetop setting, heat a nonstick skillet to medium on the cooktop. Add the onions, and cook until translucent and tender, about 6-8 minutes. Transfer into the slow cooker.
Once the onions are cooked and in the slow cooker, stir in uncooked brown rice. Add the broth, tomatoes, zucchini, bell pepper, Italian seasoning, turmeric, and cayenne, and mix well.
Cover and cook on LOW for 4 hours or on HIGH for 2 hours until liquid is absorbed.
Add peas and artichokes and cook for another 10 minutes.