Coarsely chop onions, scallions, poblanos and serrano peppers.
In a large pot, heat oil.
Add chopped vegetables and garlic. Saute for about 5 minutes, until the vegetables are softened.
Add tomatillos, water and bouillon cubes.
Add cumin and oregano and stir combine.
Bring to a boil.
Reduce to a simmer and cook for 15-20 minutes, until the vegetables are soft.
Leave to cool for a few minutes.
Transfer to a blender with the cilantro, salt, sugar and lime juice. Puree until smooth.
Transfer to glass jars and chill in the refrigerator overnight or follow canning procedures for bottling.