Cook pasta according to package directions, until al dente. Reserve ½ cup cooking water, then drain pasta and set aside.

In a 12-inch skillet, brown the butter over medium heat. When it turns light brown and begins to smell nutty, add the garlic and sage. Cook for 1 minute or until fragrant.

Add the mushrooms and salt. Cook until browned and the edges turn crispy, about 8–10 minutes.

Add the pasta and gently toss. Add ¼ cup reserved pasta water. Add the cheese and stir; as the cheese melts and combines with the butter and the starchy water, the pasta will become creamy. (If needed, add more of the reserved pasta water, 1 tablespoon at a time.)

Add 2 teaspoons of fresh lemon juice, toss to combine.

Sprinkle with extra grated pecorino Romano or Parmesan and serve.