2 medium onions, chopped
1 1/2 teaspoons whole cumin
1 teaspoon black mustard seeds
1/8 – 1/4 teaspoon canola oil (necessary for tempering the spices)
2 teaspoons ginger paste or 1 tablespoon finely minced fresh ginger
2 teaspoons finely minced garlic
2 medium sweet potatoes, peeled and cut into 1-inch cubes
8 cups water
3 cups dried yellow split peas, picked over and rinsed
1-2 tablespoons mild curry powder (to taste)
Salt to taste (optional)
1 bunch kale