In a small saucepan, melt your butter and then brown the butter until it has a deep golden color. Stir the cold milk, and allow the butter to come back to room temp. The butter just needs to be cooled, but still liquid.

Preheat your oven to 350 degrees, and grease a 9x13 inch cake pan. Optionally, line your pan with parchment for easier removal.

In a medium bowl, stir together the flour, baking soda, baking powder, cinnamon, and salt. In a large bowl, beat together the brown butter mixture, oil, peanut butter, sugar, and brown sugar until well combined and smooth. Add in the eggs and vanilla extract. Slowly add in your dry ingredients until everything well combined and no flour pockets remain. Then stir in about 3/4 of your chopped peanuts, reserving the rest for the top.

Press the cookie dough into your prepared pan evenly. I like to use my hands to press out the dough, and then an off-set spatula to smooth out the top. Sprinkle the remaining peanuts on top. Bake for 15-18 minutes, or until golden brown all over the edges of the pan, and allow the cookies to cool completely in the pan before removing and slicing into bars. Enjoy!