Heat oil in a soup or a stockpot over medium flame. Add garlic and sliced onions and saute till the onions soften, about 2-3 minutes.
Add spinach, salt, bayleaf and ¼ cup of water. Cover and cook till the spinach wilts, approx 2-3 minutes. Turn off the flame and allow it to cool.
Pour the blended spinach mixture back into the pot and bring to a simmer over low flame. Add milk and pepper and simmer for 2 more minutes. Turn off the heat.