Preheat oven to 350 degrees F. Season shanks with salt & pepper.
Heat oil in a 6-quart Dutch oven on stovetop burner over medium-high heat. Add shank and fry for about 5 minutes until golden brown all over
Add onion, carrot, celery, broth, and ONLY 2 Tablespoons of the Masala seasoning to the Dutch oven. Mix well, cover with lid or tightly with foil, and place in the oven at 350 degrees F, undisturbed, for 2 ½ to 3 hours.
Take Dutch oven out, remove lid, and use tongs or forks to shred meat off of the shank bone. Discard the bone and any undesirable tendons or fat
Add remaining 2 Tablespoons of the Masala seasoning, the turmeric, brown sugar, and diced tomatoes to the meat mixture and combine well. Simmer on stovetop over medium-low heat for 15 minutes.
Add Greek yogurt and heavy whipping cream and simmer for 5 minutes more. Add ¼ cup of water to thin out the sauce if needed.