In a large saucepan, combine butter, sugar, milk, and cocoa powder over medium heat.
Bring to a gentle boil and let it bubble for 1 minute, stirring constantly so nothing sticks.
Remove from heat and stir in the chocolate pudding mix until it’s smooth and glossy.
Add peanut butter and vanilla. Stir until fully melted and combined.
Dump in the oats and mix until everything is coated and gooey.
Scoop spoonfuls onto wax paper or parchment-lined trays and let them cool for 30 minutes until set.