Add sugar, corn starch, and salt to a large saucepan and whisk to combine. Whisk in half and half and egg yolks. Cook over medium high heat until mixture starts to thicken.

Remove from heat and whisk in heavy cream and vanilla. Chill for several hours or overnight.

Add mixture to the ice cream freezer container. Add whole milk up to the 4 quart line. Freeze according to ice cream freezer directions.

When ice cream is thick, stir in chopped Snickers (and cherries if using).

Pack ice cream freezer with additional ice and let sit for at least two hours to set.