In a medium saucepan over medium heat, melt the butter and sugar together until the sugar has dissolved. Stir in the cocoa and milk and heat through.
Turn off the heat and add the chocolate chips, salt, peanut butter, and vanilla. Stir until the chocolate and peanut butter have completely melted.
Stir in the oats and thoroughly combine all ingredients.
Drop the mixture onto a parchment-lined baking sheet using a small cookie scoop or tablespoon.
Refrigerate until firm (approximately 30 minutes)
Notes
Store cookies in an airtight container in the refrigerator for up to 5 days.May be frozen. Store in an airtight container or freezer bag. Label and date. Freeze for up to 3 months.