In a large pot or Dutch oven, heat 1 tablespoon of water over medium heat. Add the onions, garlic, ginger and sweet potatoes with a pinch of salt. Saute for 5 minutes, or until the onions are soft. Add water a tablespoon at a time if things begin to stick.
Add the tomato juice and tomatoes, bring to a boil, then reduce the heat to medium-low. Simmer, covered, for 10 minutes.
Add the peanut butter, cumin and cayenne pepper, and stir well to dissolve the peanut butter into the stew. Simmer another 5-10 minutes, or until the sweet potatoes are fork tender.
In the pot, mash some (but not all) of the sweet potatoes with a potato masher or large fork. Add the chopped spinach, and stir to mix it into the hot stew. Simmer, covered, 2-3 minutes or until the spinach is wilted. Season with sea salt and freshly ground black pepper, to taste.
Optional: Serve over brown rice, quinoa, or my favorite--2/3 brown rice + 1/3 brown or green lentils, cooked together in a rice cooker (or pot).
Optional: Garnish with chopped cilantro, chopped roasted peanuts and lime wedge.
Peanut butter is plant-based but high in fat, so it's best to limit in your diet. I cut back on the peanut butter if I'm planning to garnish my stew with peanuts.
I prefer to use whole tomatoes, as canned diced tomatoes contain a chemical (to keep them from dissolving), which alters the flavor. Also, I find there's no match for the flavor of San Marzanos, so I always use them. Chopping whole tomatoes can make a mess! To avoid this, I empty the whole can into a large bowl and break them up them with a potato masher or just process them in the food processor.