Pat the pork medallions dry with paper towels. Season both sides with salt and pepper.
Heat the butter in a large sauté pan over medium-high heat. Sauté the veal medallions until golden, about 2 minutes per side. Do not crowd the pan-sauté in batches if necessary so that the medallions brown properly. Remove finished medallions to a platter and keep warm in a 180°F oven.
Add the stock to the sauté pan, and increase heat to high. Bring to a boil and stir for 2 minutes, until the sauce is slightly thickened. Spoon the finished sauce over the medallions and serve.