Cooking osso bucco is a journey of aroma and flavour, transforming a humble beef shank into a gastronomic experience. The key to this transformation is time and the layering of flavours, so let's get into the specifics.

Traditional Method

1. Preparation: Pat the beef shanks dry with kitchen paper and season generously with salt and pepper. Preheat your oven to 160°C (Gas Mark 3).
2. Browning the Meat: In a large, ovenproof casserole dish, heat the olive oil over medium-high heat. Brown the beef shanks on both sides, about 3-4 minutes per side. Remove the shanks and set aside.
3. Sautéing the Vegetables: In the same casserole dish, add the chopped onion, carrot, and celery. Sauté until softened, about 5 minutes. Add the minced garlic and cook for another minute.
4. Deglaze and Add Liquids: Pour in the wine to deglaze the pan, scraping off any browned bits from the bottom. Allow the wine to reduce by half. Add the chopped tomatoes and beef stock.
5. Herbs and Meat: Return the browned shanks to the casserole dish. Tuck the sprigs of thyme, rosemary, and bay leaves into the liquid around the meat.
6. Slow Cook: Cover the casserole dish with a lid or foil and place it in the preheated oven. Braise for about 2-2.5 hours, or until the meat is tender and easily separates from the bone.
7. Gremolata: While the osso bucco is cooking, prepare the gremolata by mixing lemon zest, chopped parsley, and minced garlic. Set aside.
8. Finishing Touches: Once the osso bucco is tender, remove the casserole from the oven. Discard the herb sprigs and bay leaves.
9. Serving: Place each beef shank on a plate and spoon some of the sauce and vegetables over the top. Sprinkle the gremolata over each serving for a burst of fresh flavour.

Fast Pressure Cooker Method

Using a pressure cooker can drastically reduce the cooking time for osso bucco while still keeping those rich flavours. It's a fantastic way to bring out the essence of the beef shank without spending hours by the stove.

1. Preparation: Season the beef shanks generously with salt and pepper.
2. Browning the Meat: Set your pressure cooker to the 'Sauté' or 'Brown' function. Add olive oil, and once it's hot, brown the beef shanks on both sides, about 3-4 minutes per side. Remove the shanks and set aside.
3. Sautéing the Vegetables: In the same pressure cooker, add the chopped onion, carrot, and celery. Sauté until softened, about 5 minutes. Add the minced garlic and cook for another minute.
4. Deglaze and Add Liquids: Add the wine to deglaze the pot, stirring to lift any browned bits from the bottom. Allow it to simmer for a couple of minutes. Add the chopped tomatoes and beef stock.
5. Herbs and Meat: Return the browned shanks to the pressure cooker. Add the thyme, rosemary, and bay leaves.
6. Pressure Cooking: Seal the pressure cooker and set it to high pressure. Cook for 45 minutes. Once the cooking time is up, allow the pressure to release naturally for 10 minutes, and then quick-release any remaining pressure.
7. Gremolata: While the osso bucco is cooking, prepare the gremolata by mixing lemon zest, chopped parsley, and minced garlic. Set aside.
8. Finishing Touches: Once the pressure is fully released, carefully open the lid. Remove the herb sprigs and bay leaves. If the sauce is too thin, you can set the pressure cooker back to 'Sauté' and simmer to reduce it to your desired consistency.
9. Serving: Serve the beef shanks with some of the sauce and vegetables, and sprinkle the gremolata over each serving for a burst of freshness.

Using a pressure cooker not only makes the process quicker but also locks in the flavours wonderfully, making it a viable alternative for those who are short on time but still wish to enjoy this kitchen classic.