Pat the boneless skinless chicken breasts dry with paper towels, then season both sides evenly with the fine sea salt, freshly ground black pepper, garlic powder, and dried Italian seasoning.

Heat the olive oil in a large skillet over medium-high heat. Add the seasoned chicken breasts in a single layer and cook for 5 to 6 minutes per side, or until golden brown and cooked through. Transfer the chicken to a plate and cover loosely to keep warm.

Reduce the heat to medium and add the unsalted butter to the same skillet. Once the butter has melted, add the sliced cremini mushrooms and cook, stirring occasionally, for 5 to 6 minutes, until the mushrooms are browned and have released most of their moisture.

Stir the minced garlic into the mushrooms and cook for about 30 seconds, just until fragrant, being careful not to let it brown.

Pour in the low-sodium chicken broth, scraping up any browned bits from the bottom of the skillet with a wooden spoon. Let the mixture simmer for 2 to 3 minutes to reduce slightly.

Lower the heat to medium-low and stir in the heavy cream. Bring the sauce to a gentle simmer, then add the freshly grated Asiago cheese and crushed red pepper flakes if using. Stir continuously for 2 to 3 minutes, until the cheese has melted and the sauce has thickened slightly.

Return the cooked chicken breasts and any accumulated juices to the skillet, nestling them into the creamy Asiago mushroom sauce. Spoon some of the sauce over the chicken and let everything simmer together for 3 to 4 minutes to warm through and allow the flavors to meld.

Sprinkle the chopped fresh parsley over the chicken in the creamy Asiago mushroom sauce just before serving. Taste the sauce and adjust seasoning with a little more salt and pepper if needed, then serve hot.