Rinse and soak the red lentils and set aside in a bowl
In a big pan, heat oil on medium heat
Add in slit green chili and all the whole spices. Let it toast for 1-2 minutes until fragrant and start to sizzle
Mix in fresh garlic and onions. Saute until onions are soft and browned
Mix in blended tomatoes and the rest of the spices. Let it simmer on low until it thickens a bit
Mix in tomato paste and dried fenugreek leaves. Let it cook for 5-10 minutes
In a separate pot, boil lentils until soft (10-15 minutes)
While that is blending, remove the whole spices from the curry base and blend until smooth
When the lentils are cooked, strain the water and add the lentils to the blended curry. Add a splash of liquid if necessary
Let it all cook together
When serving, add in lemon juice, fresh coriander, and hot tarka. Enjoy over a bowl of basmati rice or naan.