In a microwave-safe bowl, combine white chocolate chips, sweetened condensed milk, and butter. Microwave in 30-second increments, stirring in between each until completely melted.
Stir white chocolate mixture until thoroughly combined and allow a few minutes to cool slightly. Add food coloring and gently swirl into white chocolate mixture with a fork.
Line your 8x8 baking pan with foil and pour the white chocolate mixture into the pan. Sprinkle the Valentine hearts or other red and pink sprinkles on top and gently press them into the fudge.
Refrigerate the Valentine fudge for a minimum of 2 hours. Remove the fudge by the foil from the pan and lay on a flat surface. Cut into squares and serve!