Soak the lentils in cold water for 1-2 hours. Drain, rinse and set aside.
Press the sauté button, add the oil and allow it to heat up for a minute. Add the cumin seeds and mustard seeds to the pot. Once the cumin seeds brown and the mustard seeds begin to pop, add the onion. Stir-fry for 4-5 minutes or until the onions begin to soften.
Add the garlic and ginger and stir-fry for 30 seconds.
Add the tomatoes and spices. Stir-fry for 4-5 minutes, or until the tomatoes soften.
Add the lentils and water and give everything a good mix.
Secure the lid, close the pressure valve and cook for 10 minutes at high pressure.
Naturally release pressure.
Stir in the dill leaves and serve.