- Dissolve each box of red jello into separate plastic containers using only 1 cup of boiling water for each box. Mix well to ensure combined. Cool down and cover with plastic wrap. 
- Chill overnight or at least 24 hours to set. 
- The next day in a bowl add your gelatin and pour two cups of boiling water over top to bloom the gelatin. Stir well. 
- Let cool a little and stir in sweetened condensed milk until cool to touch. 
- Cut the red jello into small similar shaped cubes or use a heart shaped cookie cutter to create heart shapes. 
- Carefully place in a 9x11 casserole dish. Pour cooled gelatin and milk mixture over red jello, cover with plastic wrap and chill over night. 
- Using a flat thin small knife or spatula, carefully cut around the side of the casserole dish to loosen sides. Slide spatula along bottom and remove pieces carefully. 
- Best served immediately however it will keep in your refrigerator for a day or two.