Mix about ¾ teaspoon of Kosher salt into each cup of water. (I make 2 cups for 2 apples)
Immerse your apple slices in this salty water for 10-15 minutes.
Drain
The salt flavor is very mild on the apple's surface—in testing, tasters didn't even notice it. The good news is that a quick rinse under cold running water washes away any traces of salt, but I don't bother with the rinse.
Store in an air-tight container, and they will last days in the refrigerator!
Video
Substitute ½ teaspoon of table salt for the ¾ teaspoon of kosher salt per cup of water.
Notes
Substitute ½ teaspoon of table salt for the ¾ teaspoon of kosher salt per cup of water.