Wash and soak chana dal and toor dal for 30 minutes. Boil in a pressure cooker with 5 cups of water, a pinch of turmeric, and salt.
Heat 4 tbsp cooking oil and add cumin seeds. When it crackles, add chopped garlic and ginger.
Then add chopped onion and fry till light brown followed by tomato and green chilies. Fry for 1 minute.
Add all the spice powders – 1 tsp red chili powder, 1 tsp cumin powder, 1 tsp coriander powder, 1 tsp amchur powder, and 1/2 tsp garam masala powder. Fry the masala well by adding a few drops of water till the raw smell disappears. (fry on low flame for 5 minutes)
Now add boil lentils and stir well. Season with salt and lemon juice. Cover and cook the dal for 10 minutes on low flame.
Prepare tadka by heating 1 tbsp cooking oil and 1 tbsp butter in a small pan. To this add cumin seeds, chopped garlic, chopped green chili, and dry red chili. Saute for a few seconds and pour this over the dal.
Serve hot with Roti or steamed rice.