Clean the mushrooms how you desire, then slice them thinly and set aside.
Create a slit down one side of the sausage and remove the casing. On a large, flat plate, mash the sausage mince with a fork until its broken apart.
Pour 3-4 tbsp of EVOO into a pan and add the crushed garlic, then add 2 tbsp of water before turning on the heat to medium.
Add the mushrooms and mix them in well using a wooden spoon. After 2 minutes, add the sausage and mix again.
Add a splash of dry white wine (Optional) or a little water then season with salt and pepper to taste. Add butter and chopped parsley, spreading the butter evenly in the pan, until it melts and combines all the ingredients well. Lower the heat and cook for 10 minutes
Bring a pot of water to a boil, add 1 tbsp of sea salt, allow it to dissolve then add the tagliatelle and cook according to the package instructions.
While the pasta is cooking, place the pan with the sausage mixture over the boiling pasta pot to keep it warm.
Once the pasta is al dente, return the pan with the sauce to the stove on a low heat. Add the pasta directly to the sauce, put aside one mug of pasta water.
Use tongs to combine. If the pasta seems dry, add a splash of pasta water and toss it really well. If you want added creaminess, add an extra splash of pasta water, quickly toss, then turn off the heat.
Finish with a generous amount of grated Pecorino cheese. Mix well with tongs or toss to combine and serve.