In a pressure cooker or heavy bottom pan, saute the onions, garlic and ginger in some olive oil.
Add the tomatoes.
Once the tomatoes are cooked, add the vegetables and lentils and stir.
Add the parsley, celery and leek and 2 cups of water.
Add salt and pepper to taste.
Cover your cooker or pan and let the soup boil until all the vegetables are soft and well cooked. For a pressure cooker, wait for 2 whistles.
Once ready, let the mixture cool slightly and puree. I use a hand blender to do that but you can transfer everything to your blender and puree it before pouring it back to your pressure cooker.
Place the soup back to boil and add the 3 remaining cups of water and let simmer. Add some salt and pepper to season, if required.
Once ready, garnish with parsley