Whisk together the milk, cream, sugar, corn syrup, salt and cornstarch.
Place over medium high heat, stirring occasionally until the mixture starts to steam. Continue to whisk and bring the mixture to a boil. When boiling throughout, remove from heat. Pass through strainer if needed.
Whisk in vanilla and peanut butter.
Cool off slightly, 5-8 minutes.
Pour into airtight container and chill 8-10 hours. While chilling, prepare peanut butter pieces.
For the peanut butter pieces
In a bowl, combine the peanut butter and powdered sugar.
Using a fork or pastry cutter, combine the two until small ball-like pieces form. If the mixture is too wet, add more sugar.
Store in airtight container until ready to use.
To freeze, remove from refrigerator and pour into ice cream freezer. Follow the directions with your freezer; each one can vary. My KitchenAid stand mixer (affiliate link) with ice cream maker attachment(affiliate link) takes about 20-25 minutes to freeze fully.
When finished, fold in the prepared peanut butter pieces and ½ cup dry roasted peanuts.
Dip into airtight container and place in deep freeze an additional 4-6 hours until hardened.