In a medium bowl, mix salt and baking soda in water until dissolved. Add pork and fold gently to combine; let stand 10 minutes.
Add garlic, rosemary, nutmeg, and pepper to pork and smear with a rubber spatula until well combined and sticky, 20 to 30 seconds (see recipe notes). Transfer pork mixture to a greased plate and form into a rough patty to fit your skillet.
Heat the oil in a skillet over medium-high heat until just smoking. Add patty and cook without moving it until bottom is browned, 2 to 3 minutes. Flip patty and continue to cook until the second side is well browned, 2 to 3 minutes longer (very center of the patty will be raw).
Remove pan from heat, transfer sausage to cutting board, and chop into ¼ inch pieces. Transfer sausage to a large bowl and add cream; set aside.
For the pasta
Cook pasta according to package directions until al dente stirring often.
Reserve 1 ½ cups cooking water, then drain pasta and return it to the pot.
While pasta cooks, return now-empty skillet to medium heat. Add 1 teaspoon oil, mushrooms, and a pinch of salt; cook, stirring frequently until mushrooms are lightly browned. Stir in remaining 2 teaspoons oil, garlic, rosemary, and pepper to taste; cook until fragrant, about 30 seconds.
Stir in wine, scraping up any browned bits, and cook until completely evaporated, 1 to 2 minutes. Stir sausage-cream mixture and ¾ cup reserved cooking water and simmer until meat is no longer pink. Remove pan from heat and stir in Pecorino until smooth.
Add sauce, parsley, and lemon juice to pasta and toss well to coat. Before serving, adjust consistency with remaining reserved cooking water as needed and season with salt and pepper to taste. To serve, top the pasta with shaved parmesan cheese and sprinkle with more parsley.
Smearing meat with a rubber spatula - The science behind it is that working seasonings into the sausage with a spatula distributes their flavor thoroughly and creates sausage texture. By “smearing” the mixture, we’re forcing the meat’s proteins to stretch out and link up together. It makes the pork appear thick and sticky.
Orecchiette is prone to nest and stuck - To prevent this, add pasta to the pot with cold water with 1 tablespoon oil. Stir often even before the water starts to boil.
Did you know that lemon juice brings out flavors in pasta? Drizzle fresh lemon juice over your pasta alla Norcina.
Make different flavor sausage - Add fennel seeds, red pepper flakes, coriander or caraway. How about caramelized onions? Why not, it’s super easy.
How much sauce? - Even if it looks like you have too much and kind of a runny sauce, the sauce will thicken and the pasta will absorb all of it as it cools down. Trust me on this. I learned it the hard way. If you don't have enough sauce your leftovers will be too dry the next day.