Step 1
Preheat an oven to 350 degrees F (175 degrees C).
Step 2
Lightly grease and flour a 9x9-inch square pan and a 9-inch round pan.
Step 3
Stir together the cake mix water vegetable oil and eggs together in a bowl until smooth.
Step 4
Mix in the strawberry gelatin until combined.
Step 5
Divide the batter evenly between the 2 prepared pans.
Step 6
Bake in the preheated oven until a toothpick inserted into the center comes out clean 20 to 25 minutes. Cool in the pans for 10 minutes before removing to cool completely on a wire rack.
Step 7
Transfer the square cake onto a large platter.
Step 8
Cut the round cake in half then arrange the cut side of the cake along two edges of the square cake to create a heart shape.
Step 9
Poke several holes on the top of the cake using the handle of a wooden spoon or spatula.
Step 9
Pour the sweetened condensed milk over the cake so that it runs into the holes; allow the milk to soak in.