In a large skillet, heat the olive oil over medium-high heat. Season the chicken with salt and pepper, then add it to the pan. Sear until browned, about 4-5 minutes each side. Once cooked, remove the chicken and set it aside.

In the same skillet, toss in the garlic and sauté for about a minute. Add the sliced mushrooms and cook until they're tender, about 5-7 minutes.

Pour in the heavy cream and stir to combine, scraping any delicious bits stuck to the bottom of the pan. Let it simmer for a few minutes until it begins to thicken.

Reduce heat to low, and whisk in the Dijon mustard and grated Asiago cheese. Stir until the cheese melts and creates a creamy sauce.

Nestle the chicken back into the skillet, spooning the sauce over each piece. Simmer for another 5 minutes.

Sprinkle with fresh parsley before serving.