In a large skillet, heat 2 tablespoons of extra-virgin olive oil over medium heat. Add 1 finely chopped shallot and a pinch of kosher salt. Sauté for about 3 minutes until translucent.

Add 8 sliced portobello mushroom caps to the skillet. Cook for 5 to 7 minutes, stirring occasionally, until softened.

In a large pot, bring salted water to a boil. Add 12 ounces of pappardelle pasta and cook until al dente, about 3 to 5 minutes. Reserve ¾ cup of pasta water, then drain.

To the skillet, add 2 minced garlic cloves, 1 teaspoon of fresh rosemary leaves, and a pinch of crushed red pepper. Stir in 2 tablespoons of tomato paste and 1 tablespoon of balsamic vinegar. Cook for 2 minutes.

Pour in ½ cup of reserved pasta water and add 2 tablespoons of unsalted butter to the skillet. Stir until the butter melts and the sauce simmers for 2 to 3 minutes.

Add the cooked pappardelle to the mushroom sauce, tossing over low heat. Add more reserved pasta water if needed for desired creaminess.

Plate the Portobello Mushroom Pappardelle hot, topping with shaved Parmigiano Reggiano.