Prepare Your Pan: Line an 8×8-inch baking dish with parchment paper and lightly coat with nonstick spray. Set aside.

Heat Treat the Flour: Place flour in a small heat-safe bowl and microwave for 1 minute to eliminate any harmful bacteria. Let it cool completely, then sift to remove clumps.

Freeze the Chocolate Chips: Place 1 cup of semi-sweet chocolate chips in a Ziploc bag and freeze while preparing the rest of the ingredients.

Make the Cookie Dough Base: In a mixing bowl, beat butter, granulated sugar, brown sugar, milk, vanilla, and salt with a hand mixer for about 2 minutes until creamy. Lower the speed and mix in the flour until well combined.

Melt the White Chocolate Mixture: In a separate bowl, microwave the white chocolate chips and sweetened condensed milk in 30-second intervals, stirring between each, until smooth and fully melted.

Combine Mixtures: Stir the frozen chocolate chips into the cookie dough base. Then, fold in the melted white chocolate mixture until fully incorporated.

Assemble the Fudge: Transfer the fudge mixture to the prepared pan. Smooth the top and sprinkle with the remaining 1 cup of chocolate chips, gently pressing them into the surface.

Chill: Cover the pan tightly and refrigerate for at least 2 hours or overnight for best results.

Serve: Once set, remove from the fridge and cut into 25 squares (5×5 grid).