First prepare an 8x8 inch square pan by lining it with aluminum foil or parchment paper and grease with butter or cooking spray.
Add the sweetened condensed milk to a medium pot or saucepan over medium heat stirring until heated, be careful not to bring to a boil.
Once heated thoroughly add the white chocolate chips and continue mix until the chips are melted and no clumps remain.
Then take off the heat, add in butter and sugar cookie mix. Whisk together until smooth.
Pour the melted fudge mixture into the prepared pan then top with sprinkles.
Refrigerator for at least 4 hours.
Remove from the refrigerator, allow to soften slightly for 30 minutes to easily cut the fudge. Cut into 16 even squares.
Store in an airtight container.
Notes
Warm Knife: Using a warm sharp knife will help you easily slice into the fudge when cutting. Simply fill a glass up with hot water and allow your knife to sit in the hot water for 30 seconds to a minutes, remove wipe off the water and slice the fudge.
Even Fudge Slices: To get the perfect even squares, start by cutting in half vertically, then those halves in half, repeat on horizontally and you will have 16 perfect 2x2 inch fudge squares.
Grease Edges Well: Ensure you grease the edges of pan down well so the fudge will slide right out of the pan.
High Altitude Directions: If you live at a higher altitude, for the best fudge results, you should lower the temperature when cooking. To be more precise, reduce the temperature 2 degrees for every 1,000 feet above sea level.
Fitted Parchment Paper: Use this hack for fuss-free lining the pan with parchment paper to make it fit perfectly.