Prep the cabbage: Wash and chop 1 purple cabbage into rough chunks. No need to be precise — everything gets blended later.
Bloom the whole spices: Heat 2 tablespoons neutral cooking oil (vegetable, canola, or avocado) in a pot over medium heat. Add 1 bay leaf, 1 teaspoons cumin seeds, 1 teaspoons fennel seeds, 1 cinnamon stick (2-inch piece), 1 whole clove, and 1 cardamom pod. Stir and cook until fragrant.
Sauté garlic and cabbage: Add 6 garlic cloves, roughly chopped and stir for 3 minutes
. Then add the chopped cabbage, 0.3 teaspoons asafoetida (hing), and 1 teaspoons salt. Sauté, stirring regularly.
Add water and simmer: Pour in just enough water to cover the cabbage (about 1 to 1½ cups). Bring to a simmer and cook for 2 minutes
only — do not overcook.
Cool the mixture: Turn off the heat. Let the pot cool to a safe handling temperature before blending.
Remove bay leaf and blend: Discard 1 bay leaf. Transfer the mixture to a blender in batches, adding a little water as needed. Blend until completely smooth.
Strain (optional): Pour blended soup through a fine mesh strainer into the pot for a silky finish. Skip this step if you prefer a thicker texture — both work great.
Season and finish: Bring the soup back to a gentle boil over medium heat. Add 0.5 teaspoons black pepper powder and taste for 1 teaspoons salt. Once boiling, stir in 2 tablespoons fresh cilantro, chopped and immediately turn off the flame. Serve hot.