• Heat the oil in a 12-inch skillet on medium-high heat until it shimmers.
• Sear the reserved turkey neck, kidneys, and heart until golden brown on all sides, 3 to 4 minutes.
• Remove the turkey parts from the pan and discard.
• Lower the heat to medium low, add the shallots, and cook, stirring often with a wooden spoon, until softened, about 1 minute.
• Add the garlic and cook until just fragrant, about 30 seconds. With the heat on low, add the Madeira and cook, scraping up the brown bits from the bottom of the pan.
• Add the flour and stir until well combined, about 1 minute.
• Add ½ cup of the reduced cider, 1 tsp. salt, and ½ tsp. pepper, and whisk continuously until combined and beginning to thicken, about 1 minute.
• Raise the heat to medium, add ½ cup of the chicken stock, and whisk continuously until the mixture comes to a low simmer and begins to thicken, 1 to 2 minutes.
• Continue this process until all the chicken stock is used and the gravy thickens to your desired consistency.
• Serve with the turkey.

TIP: MAKE AHEAD
The gravy can be made one day ahead, stored in a covered container in the refrigerator, and gently reheated over a low flame, stirring continuously, adding more stock to loosen, if necessary.