Preheat oven to 420

score duck breast, season with a little salt and some pepper

turn stove heat on to medium/medium-high

Place duck on cold pan fat side down

when fat side is brown/crisp on outside flip and sear the other side (I hold the sides of the breast on the heat for about 15 seconds each and dont know if it makes a difference)

When meat side is brown place cast iron pan in oven with duck breast in it meat side down so the fat is still cooking in the rendered fat.

After 8 minutes flip the breast to the fat side and poke the meat. It should bounce back at you in the way you would imagine a very well done steak would.

Let rest for 10 minutes in tin foil