3 ½cupsold-fashioned oats (do not use instant oats)
In a 3-quart kettle, stir together butter, cocoa powder, milk, and sugar.
Place over medium-high heat and stir until the butter melts and the mixture is smooth. Continue to cook until it begins to boil, stirring constantly.
Lightly boil for one minute (no longer or it will become hard to work with).
After one minute, remove from heat and add vanilla, chopped chocolate, and peanut butter. Stir until the chocolate and peanut butter melt then add oats and stir to completely combine. If the mixture seems too soft to form cookies, let stand for a few minutes and the oats will soak up the extra moisture.
Using a cookie scoop (or your hands), form cookies and place on parchment-lined cookie sheets.
Cool in the refrigerator or at room temperature until the cookies are firm.