Slice the pork tenderloins on a diagonal about 3/4 inch thick to make medallions. Season with salt and pepper, the with the cumin. Melt the butter in a non-stick skillet over low heat. Add the pork medallions and cook slowly until just cooked through (do not overcook or the medallions will be tough). Remove the pork from the skillet, and keep warm, covering with foil.
Add the Calvados to the skillet and with a wooden spoon scrape up any bits at the bottom. Bring to a boil and add the half and half. Stir the cornstarch into the cold milk, and add to the sauce, and bring to a simmer while stirring to thicken the sauce. Adjust the seasonings with salt and pepper, if necessary. Put the pork medallions back in the skillet just long enough to warm them up, and then fan them out on a preheated serving plate, spooning the sauce over them. Garnish with chopped parsley.