Preheat oven to 350. Line a 9x13 pan with parchment.
Cream together the butter and sugars in a large bowl.
Mix in the eggs and vanilla.
Add the dry ingredients.
Spread ⅔ of the batter in the prepared pan.
Add the chocolate chips and condensed milk to a microwave-safe bowl. Microwave at 30-second increments until 75% melted. Then just stir until the remaining chips melt.
Pour the fudge over the bottom crust. Spread it to the edges.
Drop small dollops of the remaining batter on top of the fudge.
Bake for 35-45 minutes or until golden brown.
Let cool completely.
