Toast the rolled oats in a frying pan and heat until fragrant, stirring as needed, about 2-5 minutes. Set aside to cool.
In a heatproof bowl, partially melt the butter (it should be half melted, half soft so that it’s stirrable).
Add the sugar and whisk, very well until the mix starts to look cohesive and shiny.
Add the baking soda, salt and vanilla and whisk well.
Add the egg and whisk until the mixture is light and fluffy. Whisk in the peanut butter.
Sift in the cocoa if it’s lumpy, add the flour and the rolled oats and stir to combine.
Fold in half cup of the peanut butter cups and half a cup of the candies.
Preheat the oven to 350 F. Line two greased cookie sheets with parchment paper.
Scoop the dough to about 2 tablespoons per cookie and set on the prepared pans. Arrange them so they have about a 1” diameter around them (I do about 5 cookies per pan).
If desired, in a separate bowl, make a topping mix with additional oats (they don’t need to be toasted), candies and chocolate.
Once you’ve scooped the cookies, dip them into the mix and use your hands to press bits of chocolate and candy into the top (the oats will stick on their own).
These cookies will spread so leave space around them. Bake the cookies for about 10-12 minutes.
Store in an airtight container.