1. 1. Saute the aromatics: In a large skillet over medium heat, warm the olive oil. Add the chopped onion and cook until softened, about 5-7 minutes. Stir in the minced garlic and cook for another minute until fragrant. This step helps build a deeper flavor base for your stew.

2. 2. Combine ingredients in the slow cooker: Transfer the sauteed onion and garlic to your slow cooker. Add the undrained diced tomatoes, rinsed and drained chickpeas, rinsed and drained cannellini beans, vegetable broth, diced sweet potato, sliced carrots, and diced zucchini.

3. 3. Add the spices: Sprinkle in the ground cumin, ground coriander, ground turmeric, ground cinnamon, and the optional pinch of cayenne pepper. Season generously with salt and freshly ground black pepper.

4. 4. Stir everything together: Give all the ingredients a good stir to ensure the spices are evenly distributed and everything is well combined in the slow cooker.

5. 5. Cook until tender: Cover the slow cooker with its lid. Cook on the LOW setting for 4-6 hours, or on the HIGH setting for 2-3 hours, until the vegetables (especially the sweet potato and carrots) are fork-tender. The stew should be bubbling gently.

6. 6. Taste and adjust seasoning: Once cooked, give the stew a taste. Adjust any seasonings as needed, adding more salt, pepper, or spices to suit your preference.

7. 7. Garnish and serve: Ladle the warm stew into bowls. Garnish each serving with a generous sprinkle of fresh chopped cilantro before enjoying.