Preheat the oven to 325°F. Melt 1 tbsp of the butter with 1 tbsp of the peanut oil in a large roasting pan or Dutch oven over medium-high heat. Add the onions, carrots, garlic, and ginger, reduce the heat to medium, and cook, stirring, until the vegetables soften, about 10 minutes. Remove the vegetables with a slotted spoon and keep warm.

Mix the flour, salt, and pepper together in a shallow bowl. Coat each of the pieces of beef shank in the flour and shake off the excess. Add the remaining 2 tablespoons butter and 1 tbsp oil to the pot and heat. Over medium-high heat, brown the meat well on all sides, 5 to 7 minutes. Remove the shanks to a platter.

Reduce the heat to medium and add the coriander, cumin, turmeric, and red pepper flakes. Stir for 1 minute to release the oils from the spices. Stir in 1/2 cup of the beef stock and scrape up any browned bits from the bottom of the pan. Stir in the remaining 1-1/4 cups beef stock and the coconut milk and bring to a boil.

Return the shanks and vegetables to the pan. Place the cardamom pods lightly smashed, bay leaves and cinnamon stick in a cheesecloth and make a pouch. Add the cheesecloth pouch of spices. Cover the pot, bring it to a boil, and place it in the preheated oven.

The shanks should braise until the meat is tender and shrinking away from the bone, 2-1/2 to 3-1/2 hours. Check the shanks from time to time to make sure they aren't sticking to the bottom of the pot.

When the shanks are tender, remove them to a warm platter and cover loosely with foil to keep warm. Degrease the braising liquid if necessary, and reduce it over medium-high heat to thicken slightly. Remove the spice pouch and taste for salt and pepper.

Serve the shanks on warm plates with steamed jasmine rice; ladle the sauce over them, and garnish with the cilantro.