Heat 2 tablespoons (30 ml / 1 fl oz) of oil in a deep saucepan or Dutch oven over medium heat.
Add the sliced onion and fry until soft and translucent, but not golden, about 5-7 minutes. 2.
Stir in the grated ginger, crushed garlic, and chopped green chiles.
Cook for another 2 minutes until fragrant. 3.
Add the frozen peas, hot vegetable stock, lemon juice, and garam masala. Increase the heat and bring the mixture to a boil. 4.
Once boiling, stir in the chopped mint and dill, then immediately remove the pan from the heat. 5. Carefully transfer the soup to a blender and blend until completely smooth. You may need to do this in batches. Return the puréed soup to the saucepan and reheat gently over low heat. 6.
While the soup reheats, prepare the tarka.
Pour a generous slug of oil into a small frying pan over medium heat.
When the oil is hot, add the cumin seeds and let them sizzle and turn a shade darker, about 30-60 seconds.
Add the salt, stir, and remove from the heat. 7. Ladle the hot soup into four bowls.
Garnish with the extra mint leaves and drizzle the hot cumin tarka over each serving.