Place crushed frosted flakes (or corn flakes) in a shallow dish. Stir in sugar and cinnamon until evenly combined.
Scoop out a large spoonful of ice cream (about 1 cup or 1/2 pint) using a large ice cream scoop. Roll the ice cream in the cereal crumb mixture.
Place balls of ice cream on a parchment paper-lined baking sheet. Freeze for at least 8 hours for best results. **DO NOT skip freezing or reduce the freezing time, or your ice cream balls will turn into a gooey mess.**
Heat oil to 400 degrees. in a large pot of deep fryer.
Place one ice cream ball in the oil at a time for no longer than 10 seconds, until golden brown. This is a fast process to the coating gets crispy and the ice cream stays frozen under the crust. Remove ice cream from oil and transfer to a serving bowl.
Garnish with your favorite toppings and serve immediately.
Notes
You can make a batch of the ice cream balls and keep them in the freezer until you're ready to fry. After the initial freeze, wrap any extra ice cream balls in plastic wrap and place in a Ziploc bag before returning to the freezer.
If you're frying the ice cream in a pot (vs a deep fryer) be sure there is enough oil to submerge the whole ice cream ball. You have a very short time to fry it and want to make sure the whole thing gets cooked.
Nutrition listed is for vanilla ice cream and 1 1/3 cups frosted flakes cereal.