1/2 cup thawed frozen strawberries (with juice)
4 envelopes plain, unflavored Knox gelatin
2 cups cold water
1 (6 ounce) can frozen apple juice concentrate
Mix strawberries in a blender. Stir unflavored gelatin into the cold water, and heat slowly over medium-low heat until the gelatin is totally dissolved.
Stir together the strawberries and gelatin mixture, then add frozen apple juice concentrate. Stir until apple juice concentrate has dissolved.
Spray a 9 x 12-inch pan with Pam cooking spray.
Pour the mixture into the pan and chill until firm.
To unmold, turn the pan upside down over a countertop. Using heart-shape cookie-cutters, cut hearts out of the gelatin.