Spray a 9 x 13 pan with non stick cooking spray.
In a large bowl, add the 4 packages of Strawberry Jello.
Mix in 4 cups boiling water and stir for about 2 minutes, or until dissolved.
Pour into the prepared pan and place in the refrigerator for 2 hours or until firm.
In a medium bowl add the ½ cup cold water and sprinkle the gelatin over the top, let stand for 1 minute.
Stir in 1½ cups boiling water and sweetened condensed milk, mix well and allow to cool.
Remove the firm red jello from the fridge and invert onto a cutting board.
Re-spray the same 9 x 13 pan with non stick spray.
With a heart cookie cutter, cut hearts out of the jello. Take care to cut them as close together as possible to reduce waste.
Arrange the hearts in the pan. Pour milk mixture over the hearts and place in the fridge for 2 hours until firm.
Remove and cut into squares.
Serve and enjoy!