Whip heavy cream until fluffy add the Junket and the half and half slowly. Add the corn syrup, taste as you go you may want less corn syrup or none at all. Add the almond extract and food coloring.
You have a choice here to use an ice cream freezer or just the freezer. If you use the freezer use a metal ice cube tray or any 9 x 9 pan. Preferrably lined with plastic wrap and freeze four hours. Put the cubes or scoops of cream into your blender or food processor and whip. At the end add the pistachios and stir up good. Put it back in the freezer and freeze overnight.
For ice cream freezer: I use the kitchenaid but you can use any kind you have. Just pour the cream mixture from step one into the freezer bowl and let Stir for 15 to 20 minutes. Do NOT put the mixture on 2 or higher it will melt the cream not make it faster.
Note you do not have to whip the cream for the freezer bowl but it does make it creamier and gives it more volume.
If you have never used Junket you can find it next to the ice cream above the syrups usually if you cannot find it use vanilla pudding instead. Enjoy