Preheat oven to 325 degrees Fahrenheit and lightly grease a very large and deep dish. Season short ribs on all sides with salt and pepper.

Preheat a large heavy pan over medium high heat. Add oil and sear short ribs in batches on all six sides until they are deeply browned. Place seared short ribs into prepared baking dish. Once they are all seared, drain the pan, leaving only a few tablespoons of the fat.

Add in carrots, celery and onion, and stir for about five minutes until they begin to soften. Move veggies to the sides of the pan and add tomato paste. Stir and slowly incorporate veggies. Sprinkle flour and stir again for two minutes to allow flour to cook. Add in wine, bay leaf and thyme. Use a wooden spoon to mix, making sure to scrape up any bits on the bottom of the pan.

Cook for four minutes to allow the wine to slightly reduce and thicken. Pour in sauce and stock and stir. Bring mixture to a boil, give it a taste and add a small pinch of salt and pepper if necessary. Pour sauce over the short ribs.

Cover pan with a layer of Gefen Parchment and then tightly wrap with foil. Place in the oven and bake for about three hours (time will vary depending on size of your ribs), checking on them after two hours and every 30 minutes after that. They are ready when the ribs are fork-tender! Serve over mashed potatoes or with good crusty bread.