Heat 2 tablespoons of extra-virgin olive oil in a large skillet over medium heat. Add 1 finely chopped shallot with a pinch of kosher salt and sauté for about 3-4 minutes until softened and translucent.

Introduce 4 sliced Portobello mushroom caps into the skillet with the sautéed shallots. Cook for 5-7 minutes, stirring occasionally.

While the mushrooms are cooking, bring a large pot of salted water to a boil. Add 12 ounces of pappardelle pasta and cook according to package instructions until al dente, about 8-10 minutes.

Return to the skillet with the mushrooms, stir in 3 minced garlic cloves, 1 tablespoon of fresh chopped rosemary, and ½ teaspoon of crushed red pepper flakes. Add in 2 tablespoons of tomato paste, 1 tablespoon of balsamic vinegar, and 2 tablespoons of unsalted butter.

Gently add the drained pappardelle to the mushroom sauce in the skillet, tossing to coat the pasta thoroughly.

Plate your Portobello Mushroom Pappardelle elegantly, then garnish with shavings of Parmigiano Reggiano or Parmesan cheese. Serve immediately.