Preheat oven to 350 degrees. Line a 8x8 inch baking pan with parchment paper, leave enough overhand for the sides. Set aside. Remove creem cheese from the refrigerator and let it sit out while you bake the hearts.
In a mixing bowl combine the cake mix, egg, vegetable oil, half & half and vanilla. Use a large spoon to mix everything together. Batter will be very thick and seem a little dry so be patient to incorporate all the ingredients, it may take a few minutes. Spoon the batetr into the lined baking pan and use a spoon or spatula to evenly spread the batter out. Again, the batter is thick so be patient. Bake in the oven for 20 to 25 minutes. The batter may seem under-done in the middle but this is fine, it will set as it cools. Do not over bake. Remove from oven and allow to cool completely.
Once the red velvet "cake" has cooled completely, transfer it to a clean work surface by lifting up the sides of the parchment paper from the pan. Make sure to leave the parchment paper underneath the red velvet cake. Use a heart shaped cookie cutter to punch out hearts and set them to the side.
Make the frosting: Place the cream cheese in a mixing bowl and beat it on medium speed for 2 to 3 minutes. Slowly add in the powdered sugar and half & half, beating on low speed and then working back up to medium speed until combined. Add in the vanilla extract and salt. Beat for a few extra minutes on medium speed.
Frost and decorate the hearts as desired. Store in an airtight container and keep in the refrigerator for up to 3 days.