Step 1

Cut several very shallow crosswise slashes across the skin of each duck breast about 1/2 inch apart. The cuts should only barely cut into the skin and fat; don't cut into the meat. Season skin sides with salt. Generously season meat sides with salt, black pepper, and thyme.

Step 2

Place duck breasts in a heavy-duty resealable plastic bag, squeeze out all air, and seal. Refrigerate for 1 hour.

Step 3

Fill a large Dutch oven about 2/3 full with water. Bring water to 135 degrees F (57 degrees C) over medium heat. Attach a candy or oil thermometer to the side of the Dutch oven in order to monitor and maintain the water temperature. Place a silicone hot pad into bottom of the pan to keep the plastic bag from contacting the hot bottom of the pan.

Step 4

Place plastic bag containing duck breasts in the Dutch oven, adjusting the heat as necessary to maintain the temperature at 135 degrees F (57 degrees C). Cook for 1 hour, moving the bag around occasionally and maintaining the temperature.

Step 5

Remove duck breasts from plastic bag and pat dry. Generously season skin sides with salt.

Step 6

Heat vegetable oil in a skillet over high heat. Place duck breasts with skin sides down in skillet and cook until fat renders and skin is golden brown, 5 minutes. Turn breasts over and cook until lightly browned and meat still pink in the center, 1 minute. Let duck breasts rest for 2 minutes before slicing.