Preheat the oven to 160 C / 310 F / 140 FAN / Gas 2.5.
Peel the vegetables and cut into small pieces of less than a centimetre.
Put the oil in the frying pan over a medium to high heat.
Season the steaks with salt and pepper on both sides just before adding them to the pan.
Sear for 2 minutes to get a good crust.
Turn the meat over with the tongs and sear for a further 2 minutes.
Transfer the steaks to the casserole dish.
Add the vegetables to the pan over a medium heat and cook for about 5 minutes, stirring regularly.
Transfer the vegetables to the casserole dish.
Add the wine to the pan for a minute and stir to make sure that all the crusty bits are loosened by deglazing the pan.
Stir in the stock, thyme and bay leaf and bring the mixture to a simmer.
Pour the liquid over the meat and add the lid.
Place in the oven and check the meat after 1.5 hours. Depending on the size and thickness it may need up to 3 hours to be tender.
Remove the meat from the dish and place on a plate covered with foil.
Skim off any fat that has risen to the surface and remove the bay leaf.
Use the potato masher to mash the vegetables into the gravy. If you prefer you could use a liquidiser or stick blender.
Check the seasoning and the thickness of the gravy. For thicker gravy, reduce the liquid over a medium heat or mix a teaspoon of cornflour with water and stir over a low heat.
Serve the featherblade steak with the rich gravy poured over the top.