Add the stock, heavy cream and thyme. Bring to a simmer over medium high heat. Adjust the heat and cook at a slow simmer until the sauce has thickened enough to coat the back of a spoon. Season with salt and pepper to taste. Add hot sauce to taste if using. Turn off the heat and add the oysters to the sauce. Stir gently to combine and let sit off of the heat for about 3 minutes, just enough to cook the oysters