Measure out all the ingredients and have them ready to go.
In a bowl, mix together the sugar, unsweetened cocoa powder, and cream of tartar.
Melt the butter in a deep pan, then add the warm whole milk.
Add the sugar mixture to the butter and milk mixture and stir until the sugar has completely dissolved.
Bring the mixture to a rolling boil and let it boil for 2 minutes, monitoring the temperature to reach 230-234°F.
Remove from heat and stir in the peanut butter until melted.
Quickly stir in the quick one minute cooking oats.
Optional: Add vanilla extract.
