This is a New York Times recipe that turns grapes into a frozen treat.
De-stem Seedless Grapes to make a pound. Rinse the grapes well and let them dry completely. Place in a large ziplock bag.
Combine 2 T. lemon juice, 2 t. sugar, 1 t. kosher salt, and 1/4 t. red chili flakes or black pepper (optional) and whisk to dissolve the sugar and salt well.
Pour the mixture into the bag, then zip it up and shake well to coat the grapes.
Lay the bag flat in the freezer so that there is just a single layer of grapes (use a small pan if necessary). Freeze for at least six hours.
Serve the grapes right from the freezer and eat immediately.