Heat a sous vide water bath to 150F degrees.
Season the thighs with salt and pepper.
Place the thighs, skin side down, in a cast iron pan and heat on low until they start to sizzle. Cook for 5-10 minutes, until skin has browned.
Remove from the pan and set aside to cool slightly.
Once cool enough to handle, place the turkey thighs in a vacuum sealable bag (or ziplock freezer bag of using the water displacement method described above) along with the duck fat, sage, garlic, apple and paprika.
Vacuum seal the bag and cook in a 150F degree sous vide water bath for 12 hours.
Remove the bag from the sous vide cooker. Open the bag and remove the turkey thighs.
Strain the bag juice and reserve for the gravy.
Heat a cast iron skillet over medium heat and add the thighs, skin side down. Cook for 3-5 minutes, until the skin is golden and starts to crisp.
Remove and serve with turkey gravy (below).