01 -
Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.
02 -
In a large bowl, cream together softened butter, smooth peanut butter, brown sugar, and granulated sugar until smooth and fluffy. Incorporate the egg and vanilla extract, mixing until well combined.
03 -
In a separate bowl, whisk together all-purpose flour, baking powder, baking soda, cornstarch, and salt. Gradually add the dry mixture to the wet ingredients and mix just until no streaks of flour remain.
04 -
Using a large cookie scoop, portion nine equal dough balls. Roll each between your palms, gently flatten to approximately 1 inch thickness, then freeze the discs for 15 minutes.
05 -
Arrange dough discs on the prepared baking sheet and bake for 12 to 13 minutes until edges are lightly golden.
06 -
Melt milk chocolate chips together with vegetable oil in 30-second intervals in the microwave, stirring thoroughly between each interval until smooth.
07 -
While cookies are hot, spread melted chocolate evenly on top. Generously top each cookie with muddy buddies. Allow to cool on baking sheet until set.