Butter one side of sliced bread. Heat a skillet over medium-high heat and crisp the ham a slice or two at a time, 30 seconds on each side, and let cool on a paper towel-lined plate. Add the butter to the skillet and sauté the apples to tender crisp. Season with a hint of cinnamon, a little nutmeg and a pinch of salt, then deglaze with Calvados.
Build the sandwiches with soft, mild melting cheese, crispy Serrano ham, apples and Manchego. Grill to golden in a skillet over medium heat covered loosely with foil, then turn and press for 7-8 minutes.