In a medium sized saucepan, combine the sugar, cornstarch, cocoa, and salt.
Add a little bit of the milk (about ¼ cup) and whisk until a paste forms.
Slowly add more milk, whisking well in between additions.
Once all the milk has been added, heat over medium heat.
In the same measuring cup you used to measure the milk, crack open the two eggs. Set aside.
As it heats, whisk, whisk whisk the milk mixture.. Don’t stop whisking!
Once the mixture has boiled and thickened, pour about a ¼ cup into the eggs. (just eyeball it) Whisk well. Continue adding a small amount of the thickened mixture to the eggs, whisking well in between each addition. Once you’ve added about half the mixture into the eggs, then transfer all the egg mixture back into the pot.
Whisk, whisk, whisk and cook one minute.
Remove from heat and add in the vanilla, butter, and ½ cup of peanut butter. Take a taste. Does it taste peanut buttery enough for you? If yes, then you’re done. If not, add a bit more peanut butter until it meets your peanut butter satisfaction.