Heat oil in a heavy bottom pan.
Add halved baby potatoes to the oil and fry for 5 minutes. Once the potato is slightly roasted, remove from oil with a slotted spoon. Keep aside.
To the same pan, in the remaining oil add whole spices. Let it become aromatic.
Add chopped onions. Cook onions till soft and starts to brown.
Add Ginger-Garlic paste. Cook untill the raw smell goes off.
Add blanched tomato. Cook till the Onion-Tomato mixture starts to come together.
Add all the spices. Cook the mixture till oil start to ooze from the sides.
Add Lamb pieces. Cook for 5 minutes on medium heat. This step is required to brown the meat a little bit befor putting in the slow cooker.
Then shift everything to the pre-heated slow cooker.
Cook on low heat for 4-5 hours or 2.5 - 3 hours on high temperature. Stir a couple of time in between.
If required add half - one cup of hot water for thinner gravy.
Garish with fresh coriander and serve with rice/naan/paratha .