Begin by lining an 8×8-inch baking dish with parchment paper and lightly spraying it with nonstick spray. Set this aside for later use.
In a small heat-safe bowl, place the all-purpose flour. Microwave the flour for 1 minute, then set it aside and allow it to cool completely. Once cooled, sift the flour to eliminate any small clumps.
Take 1 cup of semi-sweet chocolate chips and place them in a Ziploc bag. Set the bag in the freezer while you prepare the rest of the recipe.
In a medium-sized mixing bowl, use a handheld mixer to cream together the butter, granulated sugar, light brown sugar, milk, vanilla extract, and salt for about 1½-2 minutes.
Lower the mixer speed to low and gradually add the sifted flour, mixing just until all ingredients are well combined. Set this mixture aside.
In a heat-safe medium-sized bowl, combine the white chocolate chips and sweetened condensed milk. Heat in the microwave for 30 seconds at a time, stirring well after each interval, until the mixture is completely melted and smooth.
Retrieve the Ziploc bag containing the frozen chocolate chips from the freezer. Use a wooden spoon to stir these frozen chips into the buttery flour mixture.
Pour the melted white chocolate mixture into the cookie dough. Stir gently until all ingredients are fully combined.
Transfer the cookie dough fudge mixture into the prepared baking dish, spreading it evenly.
Sprinkle the remaining 1 cup of chocolate chips evenly over the top of the fudge. Lightly press the chips into the surface. Cover the dish tightly and refrigerate for at least 2 hours or overnight.
Once chilled, remove the fudge from the refrigerator and cut it into squares, making 5 pieces across and 5 pieces down.
