Cardamom and garam masala add subtle spice to split peas and sweet potatoes. Directions for making on the stove and for the slow cooker. I like to add a little curry powder to spice it up even more! Adapted from Whole Foods.
Stovetop method: Soak the peas in water to cover overnight. Drain and rinse.
Bring vegetable broth to a boil in a medium pot. Add soaked peas, sweet potato slices and cardamom pods. Reduce heat to a simmer and cover. Simmer for an hour.
Heat butter in a skillet over medium heat. Add onions, garam masala, curry powder if using and cumin and cook for 10 minutes, stirring often. When sweet potatoes and peas are tender, add the spiced onions to the pot. Stir and cook 5 minutes more. Remove cardamom pods and season the soup with lemon, cayenne, salt, and pepper to taste. Add a little sugar if desired.
Slow Cooker method: Place peas, broth, sweet potato and cardamom pods in a slow cooker. Cook on high for 4 to 6 hours or on low for 6 to 8 hours, adding additional broth or water to thicken if needed. When ready to serve, heat butter in a skillet over medium heat. Add onions, garam masala, curry powder if using and cumin and cook 10 minutes, stirring often. Add the spiced onions to the slow cooker. Stir, cover and cook 15 minutes longer on high heat. Remove cardamom pods and season the soup with lemon, cayenne, salt and pepper. If you like add a little sugar to taste.