In a pot over medium heat, add olive oil. Add onions, leek, cumin and cook until onions have caramelized (about 7-8 minutes). Add chicken broth and bring to a boil. Lower the heat, cover and simmer for 15 minutes.
Add peas and simmer for 5 minutes. Transfer mixture to a blender and blend until smooth.
Return soup to the pot and stir in milk. Transfer the soup to a tupperware container, seal and refrigerate for at least 2 hours.