Set the oats in a large frying pan over medium low heat. Cook to warm up the oats and toast them, stirring as you do. When you start to smell the oats, turn off the heat and set the pan aside to cool.

In a medium or large heatproof bowl, set the butter. Microwave it for 60 seconds, until it’s almost but not fully melted.

Whisk in the vanilla and salt, then add the sugars and whisk for at least a full minute, the butter will start to look less separated as you do.

Crack in the egg and whisk well, as you whisk it the mix will turn shiny and thick.

Add the m&ms and chopped chocolate and mix. Cover the dough and set in the fridge for 2 hours.

Preheat the oven to 350 F. Line two baking sheets with parchment paper (I tend to grease mine first so the paper doesn't slide around).

Scoop the dough onto the sheet, in about 2 tablespoon mounds per cookie. Leave a one inch diameter border, at least, for the cookies to spread.

Chop chocolate peanut butter cups into quarters then press 3-4 pieces of the cups onto the top of each cookie dough mound.

Bake the cookies for about 12 minutes, until the edges are golden and the middles don’t look wet.

Store leftovers in an airtight container.