Early in day:
take the tenders off (the flap meat on the non-skin side). This doesn’t have to be done, but it will make the meat easier to cook throughout. Save them for another time, or do what I mention below.
Cut off as much of the skin and fat around the meat. You can see my photos.
Cut through skin only down to the meat. This is for the rendering process.
Salt and pepper - more on skin side and less on meat side.
Put on rack to air dry in refrigerator for a few hours. (salting early is one of the ways to make the meat more tender)
* If you want to (which is a good idea) put all of the skin and fat from the cuttings in a sauce pan on low heat. Render the duck fat. I got about a cup of duck fat from these 5 breasts. You can cook the potatoes in it, and it will be fantastic! Or eggs the next morning. Or anything you would cook using butter, use the duck fat instead.
Take breasts out of fridge 2 hours before you plan on cooking. They should be room temp. Plan on about 30+ minutes for cooking and resting time.
Pre-heat oven 400 degrees and place a baking pan in the oven to heat.
On stove, heat a cast iron pan or carbon steel pan. Get the pan hot, then turn to low, or medium low depending on your stove. Put the breasts in skin side down. If needed, you can do one breast at a time. This is rendering the duck fat and allowing the skin to brown perfectly. It’s important to cook it slowly to render as much of the fat without burning the skin. It will take more than 5 minutes, but less than 10. Keep an eye on them and keep pushing down with a spatula to have an even browning.
Take breast off heat, pour off duck fat (you can save this too, but it will be more brown), and put back on stovetop medium high heat. Put duck breast back on the skillet, skin side down for one minute at most. Turn over skin side up, put a dollop of butter - tilt pan and with a spoon keep putting the melted butter over the top of the breast. Have you seen this before? I like to sit at food bars and watch them, so maybe you’ve seen them do this. My grandfather always did that too. Do this just for a minute at most.
Put the breast skin side up in the pan in the oven and pour juices over the top. Cook until it’s 115 degrees, maybe 5 minutes or more.
Rest on a plate covered with foil for at least 15 minutes (the internal temp will go up at least 10 degrees if not 15). I think mine ended up being 128, and I thought it was perfect. But if you like it more done, then cook until 120. I usually let it rest until I see the number starting to go down instead of up on the thermometer, about 15 or 20 minutes.
Thinly slice against the grain at an angle.
* if cooking the duck tenders - after putting the duck in the oven, put tenders in the pan on the stove with the butter. Cook flipping once only a few minutes. Then let them rest with the duck breasts. These will be tender (as long as they were salted early in day) and more well done.