Place a large pot of water on to boil for the pasta.
Place a large frying pan over a medium high heat and add the mushrooms - you may need to do this in batches
Fry for about 5 minutes, only turning a few times, until the mushrooms are golden and brown and have released most of their moisture. Remove from the pan, frying your second batch if necessary then, when all the mushrooms are cooked, add the butter. Allow the butter to melt then add the crushed black pepper, sliced shallot and garlic and cook for 5 minutes to allow everything to soften. Add the mushrooms back into the frying pan and give everything a good stir to combine.
Meanwhile, in a large bowl, combine the egg yolks and parmesan.
Cook your pasta according to the packet instructions and when cooked, remove with a slotted spoon into the bowl with the egg yolks and parmesan. Mix vigorously, until you begin to create a sauce. Now, add in enough pasta water to loosen everything to a double cream consistency - it should be a smooth and silky sauce, not too watery. Now, mix through your golden mushrooms and stir everything to combine. Serve with extra black pepper and parmesan.
Notes
A good selection of mushrooms takes place of guanciale in this carbonara. They gives this dish it's depth and meatiness!