Firstly, make the turkey and mushroom stock. In a pan, heat up the turkey stock and bring to a boil. Once boiling, remove from heat and add pour over the dried mushrooms into big jug. Leave this wonderfully umami mixture to then leave sit for half an hour.
Whilst the stock is sitting, you can begin to make the filling. In a heavy-based frying pan, add the butter and place on a medium-high heat. Once the butter has melted, add to the pan the flour. With a wooden spoon, mix to form a paste (commonly known as a beurre manié). Once the beurre manié has been made, you can slowly start to incorporate the mushroom and turkey stock by continuously stirring the mix whilst adding in the stock into the pan until a loose sauce has formed. Once all the stock has been added, add the cheese last thing and mix it in well.
In a separate pan, gently caramelise the bacon lardons. Once the bacon is browned, add the onions, knob of butter, garlic, fresh mushrooms and rosemary to the pan and gently soften. Once the mixture has been cooked and there is a wonderful bacon-y scent in the air, add this mixture to the sauce that you made earlier. Then, add in the turkey and mix well all together. This can be left to one side whilst you make the pastry.
To make the pastry, mix the suet, flour, baking powder water and salt in a bowl together to form a dough. The trick here is that you don't want to knead it together for too long, but you do want to mix it as quickly as possible. It shouldn't really be a sticky dough, just nicely bound together.
Now, to put your suet pudding all together. What you need to do is lightly butter an oven-proof pudding bowl. Before you roll out the pastry, take approximately a quarter of the dough off and leave to one side. This will form the lid for your suet pudding. Roll out the remaining pastry to around a cm thick. Line the bowl with the pastry and make sure there's no cracks. Add the filling to the the pastry bowl and roll out the lid to a cm thick. Pop the lid on top of the bowl of delicious filling and crimp the edges together.
Get a square of tinfoil and parchment that is big enough to cover the top of the suet pudding. Cover the bowl with and then with the tinfoil. With a piece of string, tie the tinfoil and parchment to the bowl to seal.
To cook the suet pudding, in a deep saucepan place a plate upside down with the suet pudding on top so it doesn't touch the base of the pan. To the pan, add enough water to come to the bottom of the pudding bowl. Put the pan on the stove and bring it to a gentle simmer. Simmer for 2 1/2 hours, topping up the water when needed.
Finally, the pièce de résistance, after 2 1/2 hours is finished, gently turn the pudding out of the bowl onto a plate, trying not to crack it if possible! Serve with sautéed greens and any sides that you wish!