Melt the unsweetened chocolate in a double boiler. Whisk in the cocoa powder, then gradually whisk in the milk. Keep whisking until well combined. Set the mixture aside to cool.
In a mixing bowl, whisk the eggs for 2 minutes with an electric mixer, then add the maple syrup and mix until combined. Stir in the cream and vanilla extract.
Pour the cooled chocolate mixture into the mixing bowl and stir to combine the flavors.
Remove one cup of the mixture to a bowl, and stir in the peanut butter. Add this chocolate peanut butter mixture back to the rest of the chocolate mixture and stir to combine.
Cover and refrigerate for two hours.
Transfer the mixture to your ice cream maker from a pouring-friendly container and follow the manufacturer’s instructions. Freeze for at least 2 to 3 hours. This tastes best the day it’s made.