Pre-heat the oven to 170°C, Gas Mark 3
Rinse the kidneys, pat dry and cut them in half. Remove the white cores and then cut them up into 1.5cm pieces
Put the flour into a large freezer bag and add some salt and pepper to season. Add the steak cubes and the kidneys, close the bag and give it a really good shake. Make sure that everything is coated in the seasoned flour
Heat two tablespoons of oil in a large, non stick, frying pan and begin frying the steak and kidneys in batches until each batch is nicely browned. Don't over crowd the pan, you'll end up with soggy un-browned meat!
When all of the meat has been browned, remove it from the pan and put it in the casserole. Add the onions to the pan and cook over a low heat until they are soft and golden and add them to the casserole
Use the wine to deglaze the pan. Bring it to the boil whilst carefully scraping any browned bits from the bottom of the pan. Add the tomato puree, the thyme leaves, the bayleaf and the stock. Bring the gravy together by combining everything. Take three ladlefuls of the gravy out and set aside to use as gravy later on and pour the rest of the gravy over the meat and onions in the casserole
Cover the casserole and put it in the oven to cook for 2 hours until the beef is tender. Give it a quick stir half way through the cooking time and then, when cooked, take it out of the oven and simmer on the hob for a few minutes until the sauce has thickened enough to coat the back of a spoon. Leave to one side to cool
Put the dry ingredients for the suet pastry in a bowl and give it a good mix then add the water a little at a time until you have got a soft dough. Try and avoid making a dough that's too wet. When you have a good soft dough turn it out onto a floured surface
Remove a third of the dough and set aside of for the lid. Roll the dough out into a circle to a thickness of about 5mm. Using the knob of butter to grease the pudding basin and then place the rolled out dough carefully into the basin lining it. Try to leave a lip of about 1cm which you'll need when you add the lid
Spoon the steak and kidney mixture into the basin and then roll out the remaining dough to make a lid. Carefully place the lid over the filling and push the edges together to create a seal. Trim any excess dough and, if you have enough set it aside to make a bacon pudding!
Cut out a rough circle of parchment paper and put a pleat in the middle. Cover the basin with the parchment paper and then make another circle out of tin foil and put a pleat in it. Put the foil over the basin on top of the parchment paper and then tie a piece of string around the foil to secure it to the basin. Create a handle ... you'll be grateful for it later!
Place the pudding basin into a steamer and steam for 2½ hours. When it is cooked, remove the basin from the steamer and leave to rest for five minutes. Whilst the pudding rests, heat the gravy that you set aside earlier
Cut the string around the basin and remove the foil and parchment paper. Carefully run a knife around the inside of the pudding basin to loosen the sides, then place a plate over the top and turn it upside down. Carefully lift the basin away and serve the pudding in wedges with the gravy and with some nice spring greens!! Remember that red wine you used for the gravy? It'll go really well with your steak and kidney pudding!!!