If you are working with dried mushrooms, place your mushrooms in a container and cover them with the room temperature water. Let sit for 30 minutes.
While the mushrooms steep, in a high sided sauté pan over medium high heat, heat the olive oil until it starts to ripple. Salt and pepper the chicken thighs and place them face down in the oil. Cook them until the skin is golden brown about 8 minutes*. Flip and repeat on the other side, about 4 minutes or until chicken is cooked to 165°F internally. Transfer to a plate and set aside.
Keeping the pan over medium heat, add the onion and garlic to the pan and cook for about 2 minutes, or until the onions begin to turn translucent. Add in the dry orzo pasta and stir until most of the oil and liquid is soaked up and the orzo starts to smell toasted, about 2 minutes.
Stir the white wine and marsala together and pour it into the pan to deglaze it. Use a utensil to scrape up any brown bits from the bottom of the pan. Add in the mushroom broth and mushrooms and bring to a boil. Reduce it to a simmer and cook the orzo pasta to an al dente, about 10 minutes, stirring frequently This should create a thick, creamy looking liquid, but there should still be a bit of liquid left in the pan.
Turn off the heat and stir in the cream and gruyere. Season with salt and pepper and serve immediately.
*If you remove the bones before cooking your chicken thighs, cooking time will vary. Cook the chicken thighs to 165°F internal temperature.