"Protein from split peas, chickpeas, peanut butter, and red lentils. Low-carb from yams. Sooo yummy, nutritious, and cheap. This makes a large batch, but just try to have some left for the freezer. A winner!"
Place split peas in a large container and cover with several inches of cool water; let soak for 1 hour.
Combine drained split peas, yams, onions, and red lentils in a large pot. Pour in enough water to cover by 1 inch. Stir in garlic and ginger. Bring to a boil; skim foam off the top with a slotted spoon. Simmer until yams are very tender, about 1 hour 30 minutes.
Mash split peas, yams, and lentils with a potato masher. Stir peanut butter, lemon juice, and soy sauce into the soup. Add chickpeas and frozen spinach; cook until warmed through, 8 to 10 minutes. Season with salt.