Begin by preheating your oven to 350 degrees F. Spray a 9" square baking pan with baking spray. Set aside.
In a large bowl, cream together the butter, granulated sugar, brown sugar, and peanut butter until smooth, about 5 minutes.
Add in the egg and vanilla extract. Beat again until smooth. Set aside.
In a medium bowl, whisk together the flour, oats, baking soda, and salt. Add the dry ingredients to the wet and mix until just combined.
Spread this into your prepared baking pan and sprinkle evenly with the chocolate chips.
Bake for 25-30 minutes or until set and a toothpick inserted near the center comes out clean. Allow the bars to cool.
In the meantime, prepare the peanut butter glaze by whisking together the confectioners' sugar, peanut butter, and milk. Add more or less milk to achieve a drizzling consistency.
Once your bars are cool, drizzle with the peanut butter icing. Slice, serve, and enjoy!
Extras bars can be stored in an airtight container.