Prepare the chocolate cake mix according to the package directions.
Spoon a thin layer of batter into each heart pan, filling them about one-quarter to one-third of the way.
Bake at the temperature listed on the box for 12 to 14 minutes, or until the cake is set and a toothpick comes out clean. Let the cakes cool completely.
Let the ice cream soften just enough so it’s easy to spread.
Fill each pan almost to the top with the chocolate–vanilla swirl ice cream. Freeze for about 4 hours, or until solid.
Spread a light layer of frosting over the frozen ice cream cakes and finish with the Valentine’s sprinkles.
Freeze for at least 2 more hours. Serve them right in the pans, and hang on to the lids just in case you need to save any leftovers for later.