Ensure cool whip is thawed. Beat together with eggs.
Add in the red velvet cake mix, and mix until combined. Dough will be thick.
To make well-formed hearts, use a piping bag and piping tip. Transfer the dough to the piping bag and pipe 2"-3" hearts on a silpat or parchment paper-lined baking sheet. Make sure to fill any gaps. Alternatively, if you don't want to use a piping bag or don't have one available you can make each individual heart with 2 Tbsp of dough. Drop two spoonfuls of dough so they're touching, and use a toothpick to swirl them together to form the top of the heart and drag down enough dough to make the pointy bottom. Repeat for all cookies. Sprinkle powdered sugar over the cookies. This is done best with a fine mesh strainer so you can sprinkle evenly.
Bake for 4-6 minutes at 350°. The exact time will depend on the size and thickness of your hearts. I usually prod the center of the cookies when I remove them from the oven. If they dimple and are still wet, they need another 1-2 minutes in the oven.
Remove from the oven and allow to cool. Dust with additional powdered sugar if desired (sometimes it'll absorb into the cookies in the oven).