Preheat oven to 350 degrees and line a large baking sheet with a silpat liner or parchment paper.
In a large mixing bowl cream your butter and sugars until well combined. Add your egg and vanilla mixing to combine. Add your flour, pudding mix, baking soda and salt, stirring to combine. Add chips and m and m's stirring to combine. Using a medium cookie scoop, place dough into a mini muffin tin pan. Bake for about 20 minutes, until golden and baked through. Remove from oven and with the end of a wooden spoon, press a round hole into each cookie cup without pressing all of the way through. This is where your peanut butter filling will go. Let cool completely then remove from muffin tin.
To prepare peanut butter filling, stir peanut butter and powdered sugar in a mixing bowl until well combined. Add more powdered sugar for a thicker filling if desired. Using a small cookie scoop, place a small scoop into the bowl part of the cookie.
Place melted chocolate into a zip top baggie and snip the end of the baggie. Place a small amount of melted chocolate on top of each peanut butter scoop then top with an M&Serve room temperature.