In a large pot on medium heat, add the olive oil and throw in the leeks, onions, ginger, salt and beets. Cook for 10-15 minutes or until the ingredients sweat. Do not let them brown
Add the water and boil over medium heat until the beets soften. About 1 hour
If the water starts to dry out, add some more in 1 cup increments
Carefully blend all the ingredients in the blender. Do it in batches to prevent burning or injury
Bring the blended soup back in the pot and add salt, pepper and coriander. Taste for seasoning and make the necessary corrections
Garnish with chopped green onions and a drizzle of cream (optional)