Of course, what happened next was an immediate return to the store to buy duck. I searched around locally, but was only able to find Pekin duck breasts, not the larger Moulard duck breasts which I thought would be better for prosciutto. So, I went for the easy to procure Pekin duck breast from Uwajimaya.
I prepared the breasts by rinsing them and drying them well on paper towels.
Then, I combined: 2 1/2 Cups kosher salt
1/2 Cup brown sugar
**2/25/20 update: This time, with only 4 duck breasts, I decided to cut the dry brine down by quite a bit:
½ cup kosher salt
⅛ cup brown sugar
1 teaspoon fresh ground black pepper
⅛ teaspoon ground white pepper
From 2/25/20 edit
In a glass or ceramic pan, place half the salt and sugar mixture on the bottom. Lay the duck breasts on top, and then pour the remaining mixture over top. Cover tightly with plastic wrap and refrigerate for 24-48 hours, depending on the thickness of the duck breast, to cure the duck. I had mine in for about 32 hours, which produced a slightly salty result. Next time, I'll go with 24 hours.
After curing, remove the duck from the salt mixture, rinse the salt off, and dry on paper towels.
Wrap the breasts individually in cheese cloth. Tie tightly with string.
If you have an airy and cold basement, you can hang the breasts there to dry. I opted to go with my refrigerator and rigged a couple of hanging lines.
Hang the duck for 6 to 10 days for the Pekin duck sized breasts. The ones I had seemed particularly smalls, so 6 days was all it took. But check on them daily by just lightly squeezing the duck feeling for any dry hard spots. You don't want them to get too dry.
I chose to shrink wrap each one individually. I'm not sure of the refrigerator shelf life, but I think we are good for a couple of weeks. The rest I will freeze.
Serve slicing the duck very thinly. It's salty and delicious and tastes like, well, duck prosciutto. Yum!