Place a layer of the salt/sugar mixture in pan (about ¼ to ½ of the mixture).
Use your thumb to make a slight indent in the mixture. This is where you will place the yolks. Make sure the spacing is far enough apart that the yolks will not be crowded.
Gently place yolks in the indented space.
Cover each yolk with the remaining mixture. (I take a handful of mixture and pour it over the top of each yolk. This makes a mound and will cover the yolk sufficiently.) Make sure each yolk is fully covered by the mixture.
Take the plastic wrap and cover your pan and place it in the refrigerator for 4 days.
After 4 days, set up your parchment paper or silpat on the sheet tray.
Carefully remove the yolks from the mixture and rinse them off in cold water. The center of the yolks may still be a little soft and tacky so be gentle!
Place each yolk on the parchment or silpat.
Let air dry uncovered for 2 days. (If the yolk centers are still tacky let them sit out until dried through).