Prepare the ingredients: Rinse the split peas in running water. Slice the onion.
Boil the split peas: Add about one liter of water to a pot and add the split peas. Add all the spices to the pot. Boil the ingredients on low heat for forty minutes with the lid closed. Stir the ingredients every ten minutes and add a cup of water each time.
Sauté the onion and cumin: Sauté the onion and cumin seeds in a separate pan. Preheat the pan on medium-low heat, add olive oil, and cook until the onions are caramelized.
Blend the Split pea soup: Add the cooked onion and cumin seeds to the pot and use an immersion blender to blend the soup until fine and smooth. Split peas are best served while hot. Garnish with caramelized onion to add a touch of sophistication to your split pea soup.