In a medium-sized pot, heat the veal stock and add the cheese. Whisk together until the cheese has melted. Reduce the heat to low and continue whisking for about 5 minutes. Bring the heat back up to high and boil to thicken. Turn the heat on low once it has thickened and add the creme fraiche. Bring mixture back to a boil and continue to whisk until sauce thickens. Strain the sauce using a colander, return sauce to pot, and add salt and pepper. Reduce sauce on low heat for another 5 minutes.
To prepare the veal, heat a skillet on high heat with the olive oil. Add the salt, pepper, and thyme to the skillet and let warm for 1 minute. Add the veal and sear on both sides. Remove the veal from the pan and slice thinly.
To serve, pour the sauce on a platter and place the sliced veal on top of the sauce.