Preheat oven to 350°F. Line baking sheet with parchment paper or a baking mat.
Using a stand mixer fitted with a paddle attachment, or a hand mixer, cream butter, peanut butter, brown sugar, and ¼ cup of granulated sugar for 2-3 minutes. Add egg and vanilla and mix again until well combined.
Add the salt, baking soda, and flour and mix until combined.
Portion into 1/4 cup sized balls. Place 6 on baking sheet. Using the palm of your hand press down on each ball until it makes a very thick disk, like a hockey puck.
Bake for 11-12 minutes. The cookies will appear crackly and the centers will look slightly underdone but will set as they cool.
Remove from oven and let cookies cool on pan for 5-10 minutes, the. Transfer to wire rack to cool completely.
Prepare Toppings
In a microwave safe bowl add the milk chocolate and vegetable oil. Microwave in 20 second intervals, stirring well in between until fully melted.
Drizzle 1-2 tablespoons of melted chocolate over each cookie then top with a few Muddy Buddy pieces.
Place the powdered sugar in a fine sieve and sprinkle the powdered sugar overtop of each cookie.
Serve at room temperature or warm.
Notes
Store the cookies in an airtight container at room temperature for 2-3 days or in the fridge for 3-4 days.To freeze the peanut butter cookie dough, roll into balls and flatten into the thick disks. Flash freeze on a baking sheet until firm. Transfer to an airtight container or Ziplock bag. Bake from frozen. You may need to add an additional minute onto the bake time.