Prepare a 9x9 baking dish by lining it with aluminum foil or parchment paper and then buttering or spraying with non-stick cooking spray.

Place sweetened condensed milk in a medium saucepan and heat over medium heat stirring constantly until heated through. Heat for about 3-5 minutes, being careful not to boil.

Add in white chocolate chips and continue stirring until the chips are completely melted.

Remove the saucepan from the heat and add in the butter and sugar cookie mix. Stir until the butter is melted and both ingredients are completely mixed in.

Pour the fudge mixture into the prepared pan and place sprinkles across the fudge in an even layer.

Place in the refrigerator for at least 4 hours. Remove from the refrigerator about 30 minutes before cutting. Store in an airtight container in the refrigerator.