Preheat your oven to 350-degrees. Line a 9x13 pan with aluminum foil or parchment and apply nonstick spray.
Whisk together your flour, baking powder, and baking soda. Set aside.
In a large bowl, beat together the sugars and melted butter. Add cookie butter and mix to combine. Add in the eggs, one at a time, beating after each addition, then the vanilla extract. Gradually add in the flour mixture, mixing until just moistened. The dough will be very thick. Fold in most of the Oreos and chocolate chips; save some to make the top pretty, if you want.
Press the thick dough into the pan as evenly as possible. Press in the remaining Oreos and chips.
Bake for 24-30 minutes, until the blondies are lightly golden and set.
Allow them to cool completely before cutting into bars and serving. These will keep well in an airtight container at room temperature for up to a week, if they last that long.
OM NOM NOM!